Use the OpenAL Git repository as a source for building other platforms

#2325 #3247

.github/ISSUE_TEMPLATE/1-bug.yaml

@@ -0,0 +1,42 @@
+name: Bug Report
+description: File a bug report.
+title: "[Bug]: "
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to fill out this bug report! Please attach any minimal reproduction projects!
+  - type: textarea
+    id: description-area
+    attributes:
+      label: Description
+      description: Please provide a description of the bug and what you expected to happen.
+    validations:
+      required: true
+  - type: textarea
+    id: steps-area
+    attributes:
+      label: Steps to reproduce
+      description: Please provide reproduction steps if possible.
+    validations:
+      required: true
+  - type: dropdown
+    id: version
+    attributes:
+      label: Version
+      description: What version of Flax are you running?
+      options:
+        - '1.8'
+        - '1.9'
+        - '1.10'
+        - '1.11'
+        - master branch
+      default: 2
+    validations:
+      required: true
+  - type: textarea
+    id: logs
+    attributes:
+      label: Relevant logs
+      description: Please copy and paste any relevant log output. This will be automatically formatted into code, so no need for backticks.
+      render: shell

.github/ISSUE_TEMPLATE/2-feature-request.yaml

@@ -0,0 +1,22 @@
+name: Feature Request
+description: File a feature request.
+title: "[Request]: "
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to fill out a feature request!
+  - type: textarea
+    id: description-area
+    attributes:
+      label: Description
+      description: Please provide a description of the feature!
+    validations:
+      required: true
+  - type: textarea
+    id: benefits-area
+    attributes:
+      label: Benefits
+      description: Please provide what benefits this feature would provide to the engine!
+    validations:
+      required: true

.github/workflows/build_linux.yml

@@ -16,7 +16,7 @@ jobs:
       uses: actions/checkout@v3
     - name: Install dependencies
       run: |
-        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev build-essential gettext libtool libtool-bin libpulse-dev libasound2-dev libjack-dev portaudio19-dev
+        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev build-essential gettext libtool libtool-bin libpulse-dev libasound2-dev libjack-dev portaudio19-dev libwayland-dev
     - name: Setup Vulkan
       uses: ./.github/actions/vulkan
     - name: Setup .NET
@@ -44,7 +44,7 @@ jobs:
       uses: actions/checkout@v3
     - name: Install dependencies
       run: |
-        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev
+        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev libwayland-dev
     - name: Setup Vulkan
       uses: ./.github/actions/vulkan
     - name: Setup .NET

.github/workflows/tests.yml

@@ -28,7 +28,7 @@ jobs:
         git lfs pull
     - name: Install dependencies
       run: |
-        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev build-essential gettext libtool libtool-bin libpulse-dev libasound2-dev libjack-dev portaudio19-dev
+        sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev build-essential gettext libtool libtool-bin libpulse-dev libasound2-dev libjack-dev portaudio19-dev libwayland-dev
     - name: Build
       run: |
         ./GenerateProjectFiles.sh -vs2022 -log -verbose -printSDKs -dotnet=8

Content/Editor/MaterialTemplates/Decal.shader

@@ -13,7 +13,7 @@
 META_CB_BEGIN(0, Data)
 float4x4 WorldMatrix;
 float4x4 InvWorld;
-float4x4 SVPositionToWorld;
+float4x4 SvPositionToWorld;
 @1META_CB_END
 
 // Use depth buffer for per-pixel decal layering
@@ -27,12 +27,63 @@ struct MaterialInput
 	float3 WorldPosition;
 	float TwoSidedSign;
 	float2 TexCoord;
+	float4 TexCoord_DDX_DDY;
 	float3x3 TBN;
 	float4 SvPosition;
 	float3 PreSkinnedPosition;
 	float3 PreSkinnedNormal;
 };
 
+// Calculates decal texcoords for a given pixel position (sampels depth buffer and projects value to decal space).
+float2 SvPositionToDecalUV(float4 svPosition)
+{
+	float2 screenUV = svPosition.xy * ScreenSize.zw;
+	svPosition.z = SAMPLE_RT(DepthBuffer, screenUV).r;
+	float4 positionHS = mul(float4(svPosition.xyz, 1), SvPositionToWorld);
+	float3 positionWS = positionHS.xyz / positionHS.w;
+	float3 positionOS = mul(float4(positionWS, 1), InvWorld).xyz;
+	return positionOS.xz + 0.5f;
+}
+
+// Manually compute ddx/ddy for decal texture cooordinates to avoid the 2x2 pixels artifacts on the edges of geometry under decal
+// [Reference: https://www.humus.name/index.php?page=3D&ID=84]
+float4 CalculateTextureDerivatives(float4 svPosition, float2 texCoord)
+{
+	float4 svDiffX = float4(1, 0, 0, 0);
+	float2 uvDiffX0 = texCoord - SvPositionToDecalUV(svPosition - svDiffX);
+	float2 uvDiffX1 = SvPositionToDecalUV(svPosition + svDiffX) - texCoord;
+	float2 dx = dot(uvDiffX0, uvDiffX0) < dot(uvDiffX1, uvDiffX1) ? uvDiffX0 : uvDiffX1;
+
+	float4 svDiffY = float4(0, 1, 0, 0);
+	float2 uvDiffY0 = texCoord - SvPositionToDecalUV(svPosition - svDiffY);
+	float2 uvDiffY1 = SvPositionToDecalUV(svPosition + svDiffY) - texCoord;
+	float2 dy = dot(uvDiffY0, uvDiffY0) < dot(uvDiffY1, uvDiffY1) ? uvDiffY0 : uvDiffY1;
+
+	return float4(dx, dy);
+}
+
+// Computes the mipmap level for a specific texture dimensions to be sampled at decal texture cooordinates.
+// [Reference: https://hugi.scene.org/online/coding/hugi%2014%20-%20comipmap.htm]
+float CalculateTextureMipmap(MaterialInput input, float2 textureSize)
+{
+	float2 dx = input.TexCoord_DDX_DDY.xy * textureSize;
+	float2 dy = input.TexCoord_DDX_DDY.zw * textureSize;
+	float d = max(dot(dx, dx), dot(dy, dy));
+	return (0.5 * 0.5) * log2(d); // Hardcoded half-mip rate reduction to avoid artifacts when decal is moved over dither texture
+}
+float CalculateTextureMipmap(MaterialInput input, Texture2D t)
+{
+	float2 textureSize;
+	t.GetDimensions(textureSize.x, textureSize.y);
+	return CalculateTextureMipmap(input, textureSize);
+}
+float CalculateTextureMipmap(MaterialInput input, TextureCube t)
+{
+	float2 textureSize;
+	t.GetDimensions(textureSize.x, textureSize.y);
+	return CalculateTextureMipmap(input, textureSize);
+}
+
 // Transforms a vector from tangent space to world space
 float3 TransformTangentVectorToWorld(MaterialInput input, float3 tangentVector)
 {
@@ -116,7 +167,6 @@ Material GetMaterialPS(MaterialInput input)
 }
 
 // Input macro specified by the material: DECAL_BLEND_MODE
-
 #define DECAL_BLEND_MODE_TRANSLUCENT 0
 #define DECAL_BLEND_MODE_STAIN       1
 #define DECAL_BLEND_MODE_NORMAL      2
@@ -153,7 +203,7 @@ void PS_Decal(
 	float2 screenUV = SvPosition.xy * ScreenSize.zw;
 	SvPosition.z = SAMPLE_RT(DepthBuffer, screenUV).r;
 
-	float4 positionHS = mul(float4(SvPosition.xyz, 1), SVPositionToWorld);
+	float4 positionHS = mul(float4(SvPosition.xyz, 1), SvPositionToWorld);
 	float3 positionWS = positionHS.xyz / positionHS.w;
 	float3 positionOS = mul(float4(positionWS, 1), InvWorld).xyz;
 
@@ -166,8 +216,9 @@ void PS_Decal(
 	materialInput.TexCoord = decalUVs;
 	materialInput.TwoSidedSign = 1;
 	materialInput.SvPosition = SvPosition;
-	
-	// Build tangent to world transformation matrix
+	materialInput.TexCoord_DDX_DDY = CalculateTextureDerivatives(materialInput.SvPosition, materialInput.TexCoord);
+
+	// Calculate tangent-space
 	float3 ddxWp = ddx(positionWS);
 	float3 ddyWp = ddy(positionWS);
 	materialInput.TBN[0] = normalize(ddyWp);

Content/Editor/MaterialTemplates/Features/ForwardShading.hlsl

@@ -27,6 +27,7 @@ TextureCube EnvProbe : register(t__SRV__);
 TextureCube SkyLightTexture : register(t__SRV__);
 Buffer<float4> ShadowsBuffer : register(t__SRV__);
 Texture2D<float> ShadowMap : register(t__SRV__);
+Texture3D VolumetricFogTexture : register(t__SRV__);
 @4// Forward Shading: Utilities
 @5// Forward Shading: Shaders
 
@@ -147,6 +148,18 @@ void PS_Forward(
 	// Calculate exponential height fog
 	float4 fog = GetExponentialHeightFog(ExponentialHeightFog, materialInput.WorldPosition, ViewPos, 0, gBuffer.ViewPos.z);
 
+	if (ExponentialHeightFog.VolumetricFogMaxDistance > 0)
+	{
+		// Sample volumetric fog and mix it in
+		float2 screenUV = materialInput.SvPosition.xy * ScreenSize.zw;
+		float3 viewVector = materialInput.WorldPosition - ViewPos;
+		float sceneDepth = length(viewVector);
+		float depthSlice = sceneDepth / ExponentialHeightFog.VolumetricFogMaxDistance;
+		float3 volumeUV = float3(screenUV, depthSlice);
+		float4 volumetricFog = VolumetricFogTexture.SampleLevel(SamplerLinearClamp, volumeUV, 0);
+		fog = CombineVolumetricFog(fog, volumetricFog);
+	}
+
 	// Apply fog to the output color
 #if MATERIAL_BLEND == MATERIAL_BLEND_OPAQUE
 	output = float4(output.rgb * fog.a + fog.rgb, output.a);

Content/Editor/MaterialTemplates/GUI.shader

@@ -20,6 +20,8 @@ float TimeParam;
 float4 ViewInfo;
 float4 ScreenSize;
 float4 ViewSize;
+float3 ViewPadding0;
+float UnscaledTimeParam;
 @1META_CB_END
 
 // Shader resources

Content/Editor/MaterialTemplates/Particle.shader

@@ -645,7 +645,7 @@ VertexOutput VS_Ribbon(RibbonInput input, uint vertexIndex : SV_VertexID)
 	materialInput.TBN = output.TBN;
 	materialInput.TwoSidedSign = 1;
 	materialInput.SvPosition = output.Position;
-	materialInput.PreSkinnedPosition = Position;
+	materialInput.PreSkinnedPosition = position;
 	materialInput.PreSkinnedNormal = tangentToLocal[2].xyz;
 	materialInput.InstanceOrigin = output.InstanceOrigin;
 	materialInput.InstanceParams = output.InstanceParams;	

Content/Editor/MaterialTemplates/PostProcess.shader

@@ -19,6 +19,8 @@ float4 ViewInfo;
 float4 ScreenSize;
 float4 TemporalAAJitter;
 float4x4 InverseViewProjectionMatrix;
+float3 ViewPadding0;
+float UnscaledTimeParam;
 @1META_CB_END
 
 // Shader resources

Flax.flaxproj

@@ -13,6 +13,7 @@
   "Configuration": {
     "UseCSharp": true,
     "UseLargeWorlds": false,
-    "UseDotNet": true
+    "UseDotNet": true,
+    "UseSDL": true
   }
 }

Flax.sln.DotSettings

@@ -73,6 +73,24 @@
 	<s:String x:Key="/Default/CodeStyle/Naming/CppNaming/UserRules/=TYPEDEF/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aa_bb" /&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CppNaming/UserRules/=UNION/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aa_bb" /&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CppNaming/UserRules/=UNION_005FMEMBER/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aa_bb" /&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Abbreviations/=CCD/@EntryIndexedValue">CCD</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Abbreviations/=GPU/@EntryIndexedValue">GPU</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Abbreviations/=ID/@EntryIndexedValue">ID</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=175CE9C669E52F4D92FD2C07848740BD/@EntryIndexedValue">&lt;NamingElement Priority="11" Title="Class and struct public fields"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="PUBLIC"&gt;&lt;type Name="class field" /&gt;&lt;type Name="struct field" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=32EB6D69783B3E4481A733193E338089/@EntryIndexedValue">&lt;NamingElement Priority="9" Title="Class and struct methods"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="member function" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=3C4E0D59F298854F9608A9B454E8FF5E/@EntryIndexedValue">&lt;NamingElement Priority="17" Title="Typedefs"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="type alias" /&gt;&lt;type Name="typedef" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=499C9026DADA2B448BCD0B2C54746A59/@EntryIndexedValue">&lt;NamingElement Priority="14" Title="Other constants"&gt;&lt;Descriptor Static="True" Constexpr="Indeterminate" Const="True" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="class field" /&gt;&lt;type Name="local variable" /&gt;&lt;type Name="struct field" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=50D2535711CE1A43A3B06EF841C36CFD/@EntryIndexedValue">&lt;NamingElement Priority="13" Title="Enum members"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="scoped enumerator" /&gt;&lt;type Name="unscoped enumerator" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=6AD3BADA1260CC4D840AB26323C51827/@EntryIndexedValue">&lt;NamingElement Priority="15" Title="Global constants"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="True" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="global variable" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=904CDCA174AACE4AA52660A247CDF9A0/@EntryIndexedValue">&lt;NamingElement Priority="7" Title="Global variables"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="global variable" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=95BCDE767C97B64DB3DAE800DBBBC758/@EntryIndexedValue">&lt;NamingElement Priority="5" Title="Parameters"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="function parameter" /&gt;&lt;type Name="lambda parameter" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="aaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=C03AE454FC2CBA43819AC75E4D6C9C8C/@EntryIndexedValue">&lt;NamingElement Priority="1" Title="Classes and structs"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="__interface" /&gt;&lt;type Name="class" /&gt;&lt;type Name="struct" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=D49E31C610641E4CAD0407DB79ACC851/@EntryIndexedValue">&lt;NamingElement Priority="8" Title="Global functions"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="global function" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=D73FBB3529BC5449B6C85BB37B26A8D4/@EntryIndexedValue">&lt;NamingElement Priority="16" Title="Namespaces"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="namespace" /&gt;&lt;type Name="namespace alias" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=DA41807CE47AEB4CBE1724C44D0B786E/@EntryIndexedValue">&lt;NamingElement Priority="6" Title="Local variables"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="local variable" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="aaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=DDF30C9A1DA74B4DBBC56D25FDF886AA/@EntryIndexedValue">&lt;NamingElement Priority="10" Title="Class and struct fields"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="class field" /&gt;&lt;type Name="struct field" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=EF70A6BF54ACE446971DDB32344C25A3/@EntryIndexedValue">&lt;NamingElement Priority="12" Title="Union members"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="union member" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CppNamingOptions/Rules/=F37818C54C323A4A80B1A478629985AE/@EntryIndexedValue">&lt;NamingElement Priority="2" Title="Enums"&gt;&lt;Descriptor Static="Indeterminate" Constexpr="Indeterminate" Const="Indeterminate" Volatile="Indeterminate" Accessibility="NOT_APPLICABLE"&gt;&lt;type Name="enum" /&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/NamingElement&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=AI/@EntryIndexedValue">AI</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=ARGB/@EntryIndexedValue">ARGB</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=LO/@EntryIndexedValue">LO</s:String>
@@ -213,6 +231,7 @@
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=YZ/@EntryIndexedValue">YZ</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PublicFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AaBb"&gt;&lt;ExtraRule Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/Environment/Hierarchy/PsiConfigurationSettingsKey/CustomLocation/@EntryValue">C:\Users\Wojtek\AppData\Local\JetBrains\Transient\ReSharperPlatformVs15\v08_f9eacea9\SolutionCaches</s:String>
+	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EFeature_002EServices_002ECpp_002ECodeStyle_002ENaming_002ECppNamingOptionsMigration/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EFeature_002EServices_002ECpp_002ECodeStyle_002ESettingsUpgrade_002EFunctionReturnStyleSettingsUpgrader/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EFeature_002EServices_002ECpp_002ECodeStyle_002ESettingsUpgrade_002ENamespaceIndentationSettingsUpgrader/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ECSharpAttributeForSingleLineMethodUpgrade/@EntryIndexedValue">True</s:Boolean>

ISSUE_TEMPLATE.md

@@ -1,19 +0,0 @@
-<!-- Please search existing issues for potential duplicates before filing yours:
-https://github.com/flaxengine/FlaxEngine/issues?q=is%3Aissue
--->
-
-**Issue description:**
-<!-- What happened, and what was expected. -->
-<!-- Log file, can be found in the project directory's `Logs` folder (optional) -->
-
-**Steps to reproduce:**
-<!-- Enter minimal reproduction steps if available. -->
-
-
-**Minimal reproduction project:**
-<!-- Recommended as it greatly speeds up debugging. Drag and drop a zip archive to upload it. -->
-
-
-**Flax version:**
-<!-- Specify version number. -->
-

README.md

@@ -57,9 +57,9 @@ Follow the instructions below to compile and run the engine from source.
   * Arch: `sudo pacman -S git git-lfs`
   * `git-lfs install`
 * Install the required packages:
-  * Ubuntu: `sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev zlib1g-dev`
-  * Fedora: `sudo dnf install libX11-devel libXcursor-devel  libXinerama-devel ghc-zlib-devel`
-  * Arch: `sudo pacman -S base-devel libx11 libxcursor libxinerama zlib`
+  * Ubuntu: `sudo apt-get install libx11-dev libxcursor-dev libxinerama-dev zlib1g-dev zenity wayland-protocols libportal-dev`
+  * Fedora: `sudo dnf install libX11-devel libXcursor-devel  libXinerama-devel ghc-zlib-devel zenity wayland-protocols-devel libportal`
+  * Arch: `sudo pacman -S base-devel libx11 libxcursor libxinerama zlib zenity wayland-protocols libportal`
 * Install Clang compiler (version 6 or later):
   * Ubuntu: `sudo apt-get install clang lldb lld`
   * Fedora: `sudo dnf install clang llvm lldb lld`

Source/Editor/Content/Create/PrefabCreateEntry.cs

@@ -117,7 +117,8 @@ namespace FlaxEditor.Content.Create
 
             private static bool IsValid(Type type)
             {
-                return (type.IsPublic || type.IsNestedPublic) && !type.IsAbstract && !type.IsGenericType;
+                var controlTypes = Editor.Instance.CodeEditing.Controls.Get();
+                return (type.IsPublic || type.IsNestedPublic) && !type.IsAbstract && !type.IsGenericType && controlTypes.Contains(new ScriptType(type));
             }
         }
 

Source/Editor/Content/Items/ContentFolder.cs

@@ -282,7 +282,7 @@ namespace FlaxEditor.Content
 
             if (data is DragDataFiles)
                 return DragDropEffect.Copy;
-            return _dragOverItems.Effect;
+            return _dragOverItems?.Effect ?? DragDropEffect.None;
         }
 
         /// <inheritdoc />

Source/Editor/Content/Items/CppScriptItem.cs

@@ -20,7 +20,7 @@ namespace FlaxEditor.Content
         }
 
         /// <inheritdoc />
-        public override string TypeDescription => Path.EndsWith(".h") ? "C++ Header File" : "C++ Source Code";
+        public override string TypeDescription => Path.EndsWith(".h") || Path.EndsWith(".hpp") ? "C++ Header File" : "C++ Source Code";
 
         /// <inheritdoc />
         public override SpriteHandle DefaultThumbnail => Editor.Instance.Icons.CPPScript128;

Source/Editor/CustomEditorWindow.cs

@@ -18,8 +18,8 @@ namespace FlaxEditor
             private readonly CustomEditorPresenter _presenter;
             private CustomEditorWindow _customEditor;
 
-            public Win(CustomEditorWindow customEditor)
-            : base(Editor.Instance, false, ScrollBars.Vertical)
+            public Win(CustomEditorWindow customEditor, bool hideOnClose, ScrollBars scrollBars)
+            : base(Editor.Instance, hideOnClose, scrollBars)
             {
                 Title = customEditor.GetType().Name;
                 _customEditor = customEditor;
@@ -64,9 +64,9 @@ namespace FlaxEditor
         /// <summary>
         /// Initializes a new instance of the <see cref="CustomEditorWindow"/> class.
         /// </summary>
-        protected CustomEditorWindow()
+        protected CustomEditorWindow(bool hideOnClose = false, ScrollBars scrollBars = ScrollBars.Vertical)
         {
-            _win = new Win(this);
+            _win = new Win(this, hideOnClose, scrollBars);
             ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
         }
 

Source/Editor/CustomEditors/CustomEditor.cs

@@ -749,6 +749,15 @@ namespace FlaxEditor.CustomEditors
             }
         }
 
+        private Actor FindActor(CustomEditor editor)
+        {
+            if (editor.Values[0] is Actor actor)
+                return actor;
+            if (editor.ParentEditor != null)
+                return FindActor(editor.ParentEditor);
+            return null;
+        }
+
         private Actor FindPrefabRoot(CustomEditor editor)
         {
             if (editor.Values[0] is Actor actor)
@@ -767,32 +776,35 @@ namespace FlaxEditor.CustomEditors
             return FindPrefabRoot(actor.Parent);
         }
 
-        private SceneObject FindObjectWithPrefabObjectId(Actor actor, ref Guid prefabObjectId)
+        private SceneObject FindObjectWithPrefabObjectId(Actor actor, ref Guid prefabObjectId, Actor endPoint)
         {
+            var visited = new HashSet<Actor>();
+            return FindObjectWithPrefabObjectId(actor, ref prefabObjectId, endPoint, visited);
+        }
+
+        private SceneObject FindObjectWithPrefabObjectId(Actor actor, ref Guid prefabObjectId, Actor endPoint, HashSet<Actor> visited)
+        {
+            if (visited.Contains(actor) || actor is Scene || actor == endPoint)
+                return null;
             if (actor.PrefabObjectID == prefabObjectId)
                 return actor;
 
             for (int i = 0; i < actor.ScriptsCount; i++)
             {
-                if (actor.GetScript(i).PrefabObjectID == prefabObjectId)
-                {
-                    var a = actor.GetScript(i);
-                    if (a != null)
-                        return a;
-                }
+                var script = actor.GetScript(i);
+                if (script != null && script.PrefabObjectID == prefabObjectId)
+                    return script;
             }
 
             for (int i = 0; i < actor.ChildrenCount; i++)
             {
-                if (actor.GetChild(i).PrefabObjectID == prefabObjectId)
-                {
-                    var a = actor.GetChild(i);
-                    if (a != null)
-                        return a;
-                }
+                var child = actor.GetChild(i);
+                if (child != null && child.PrefabObjectID == prefabObjectId)
+                    return child;
             }
 
-            return null;
+            // Go up in the hierarchy
+            return FindObjectWithPrefabObjectId(actor.Parent, ref prefabObjectId, endPoint, visited);
         }
 
         /// <summary>
@@ -826,7 +838,7 @@ namespace FlaxEditor.CustomEditors
                 }
 
                 var prefabObjectId = referenceSceneObject.PrefabObjectID;
-                var prefabInstanceRef = FindObjectWithPrefabObjectId(prefabInstanceRoot, ref prefabObjectId);
+                var prefabInstanceRef = FindObjectWithPrefabObjectId(FindActor(this), ref prefabObjectId, prefabInstanceRoot);
                 if (prefabInstanceRef == null)
                 {
                     Editor.LogWarning("Missing prefab instance reference in the prefab instance. Cannot revert to it.");

Source/Editor/CustomEditors/CustomEditorPresenter.cs

@@ -63,6 +63,11 @@ namespace FlaxEditor.CustomEditors
         /// Indication of if the properties window is locked on specific objects.
         /// </summary>
         public bool LockSelection { get; set; }
+
+        /// <summary>
+        /// Gets the scene editing context.
+        /// </summary>
+        public ISceneEditingContext SceneContext { get; }
     }
 
     /// <summary>

Source/Editor/CustomEditors/CustomEditorsUtil.cs

@@ -87,8 +87,11 @@ namespace FlaxEditor.CustomEditors
             var targetTypeType = TypeUtils.GetType(targetType);
             if (canUseRefPicker)
             {
+                // TODO: add generic way of CustomEditor for ref pickers (use it on AssetRefEditor/GPUTextureEditor/...)
                 if (typeof(Asset).IsAssignableFrom(targetTypeType))
                     return new AssetRefEditor();
+                if (typeof(GPUTexture).IsAssignableFrom(targetTypeType))
+                    return new GPUTextureEditor();
                 if (typeof(FlaxEngine.Object).IsAssignableFrom(targetTypeType))
                     return new FlaxObjectRefEditor();
             }

Source/Editor/CustomEditors/Dedicated/ActorEditor.cs

@@ -1,8 +1,5 @@
 // Copyright (c) Wojciech Figat. All rights reserved.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using FlaxEditor.Actions;
 using FlaxEditor.CustomEditors.Editors;
 using FlaxEditor.CustomEditors.Elements;
@@ -10,12 +7,14 @@ using FlaxEditor.GUI;
 using FlaxEditor.GUI.ContextMenu;
 using FlaxEditor.GUI.Tree;
 using FlaxEditor.Scripting;
-using FlaxEditor.Windows;
 using FlaxEditor.Windows.Assets;
 using FlaxEngine;
 using FlaxEngine.GUI;
 using FlaxEngine.Json;
 using FlaxEngine.Utilities;
+using System;
+using System.Collections.Generic;
+using System.Linq;
 
 namespace FlaxEditor.CustomEditors.Dedicated
 {
@@ -240,6 +239,12 @@ namespace FlaxEditor.CustomEditors.Dedicated
                 node.TextColor = Color.OrangeRed;
                 node.Text = Utilities.Utils.GetPropertyNameUI(removed.PrefabObject.GetType().Name);
             }
+            // Removed Actor
+            else if (editor is RemovedActorDummy removedActor)
+            {
+                node.TextColor = Color.OrangeRed;
+                node.Text = $"{removedActor.PrefabObject.Name} ({Utilities.Utils.GetPropertyNameUI(removedActor.PrefabObject.GetType().Name)})";
+            }
             // Actor or Script
             else if (editor.Values[0] is SceneObject sceneObject)
             {
@@ -295,16 +300,40 @@ namespace FlaxEditor.CustomEditors.Dedicated
                 // Not used
             }
         }
+        
+        private class RemovedActorDummy : CustomEditor
+        {
+            /// <summary>
+            /// The removed prefab object (from the prefab default instance).
+            /// </summary>
+            public Actor PrefabObject;
+
+            /// <summary>
+            /// The prefab instance's parent.
+            /// </summary>
+            public Actor ParentActor;
+
+            /// <summary>
+            /// The order of the removed actor in the parent.
+            /// </summary>
+            public int OrderInParent;
+
+            /// <inheritdoc />
+            public override void Initialize(LayoutElementsContainer layout)
+            {
+                // Not used
+            }
+        }
 
         private TreeNode ProcessDiff(CustomEditor editor, bool skipIfNotModified = true)
         {
-            // Special case for new Script added to actor
-            if (editor.Values[0] is Script script && !script.HasPrefabLink)
+            // Special case for new Script or child actor added to actor
+            if ((editor.Values[0] is Script script && !script.HasPrefabLink) || (editor.Values[0] is Actor a && !a.HasPrefabLink))
                 return CreateDiffNode(editor);
 
             // Skip if no change detected
             var isRefEdited = editor.Values.IsReferenceValueModified;
-            if (!isRefEdited && skipIfNotModified)
+            if (!isRefEdited && skipIfNotModified && editor is not ScriptsEditor)
                 return null;
 
             TreeNode result = null;
@@ -359,6 +388,44 @@ namespace FlaxEditor.CustomEditors.Dedicated
                 }
             }
 
+            // Compare child actors for removed actors.
+            if (editor is ActorEditor && editor.Values.HasReferenceValue && editor.Values.ReferenceValue is Actor prefabObjectActor)
+            {
+                var thisActor = editor.Values[0] as Actor;
+                for (int i = 0; i < prefabObjectActor.ChildrenCount; i++)
+                {
+                    var prefabActorChild = prefabObjectActor.Children[i];
+                    if (thisActor == null)
+                        continue;
+                    bool isRemoved = true;
+                    for (int j = 0; j < thisActor.ChildrenCount; j++)
+                    {
+                        var actorChild = thisActor.Children[j];
+                        if (actorChild.PrefabObjectID == prefabActorChild.PrefabObjectID)
+                        {
+                            isRemoved = false;
+                            break;
+                        }
+                    }
+                    if (isRemoved)
+                    {
+                        var dummy = new RemovedActorDummy
+                        {
+                            PrefabObject = prefabActorChild,
+                            ParentActor = thisActor,
+                            OrderInParent = prefabActorChild.OrderInParent,
+                        };
+                        var child = CreateDiffNode(dummy);
+                        if (result == null)
+                            result = CreateDiffNode(editor);
+                        result.AddChild(child);
+                    }
+                }
+            }
+
+            if (editor is ScriptsEditor && result != null && result.ChildrenCount == 0)
+                return null;
+
             return result;
         }
 
@@ -438,6 +505,15 @@ namespace FlaxEditor.CustomEditors.Dedicated
             Presenter.BuildLayoutOnUpdate();
         }
 
+        private static void GetAllPrefabObjects(List<object> objects, Actor actor)
+        {
+            objects.Add(actor);
+            objects.AddRange(actor.Scripts);
+            var children = actor.Children;
+            foreach (var child in children)
+                GetAllPrefabObjects(objects, child);
+        }
+
         private void OnDiffRevert(CustomEditor editor)
         {
             // Special case for removed Script from actor
@@ -459,6 +535,22 @@ namespace FlaxEditor.CustomEditors.Dedicated
                 return;
             }
 
+            // Special case for reverting removed Actors
+            if (editor is RemovedActorDummy removedActor)
+            {
+                Editor.Log("Reverting removed actor changes to prefab (adding it)");
+
+                var parentActor = removedActor.ParentActor;
+                var restored = parentActor.AddChild(removedActor.PrefabObject.GetType());
+                var prefabId = parentActor.PrefabID;
+                var prefabObjectId = removedActor.PrefabObject.PrefabObjectID;
+                string data = JsonSerializer.Serialize(removedActor.PrefabObject);
+                JsonSerializer.Deserialize(restored, data);
+                Presenter.Owner.SceneContext.Spawn(restored, parentActor, removedActor.OrderInParent);
+                Actor.Internal_LinkPrefab(FlaxEngine.Object.GetUnmanagedPtr(restored), ref prefabId, ref prefabObjectId);
+                return;
+            }
+
             // Special case for new Script added to actor
             if (editor.Values[0] is Script script && !script.HasPrefabLink)
             {
@@ -470,8 +562,37 @@ namespace FlaxEditor.CustomEditors.Dedicated
 
                 return;
             }
+            
+            // Special case for new Actor added to actor
+            if (editor.Values[0] is Actor a && !a.HasPrefabLink)
+            {
+                Editor.Log("Reverting added actor changes to prefab (removing it)");
 
-            editor.RevertToReferenceValue();
+                // TODO: Keep previous selection.
+                var context = Presenter.Owner.SceneContext;
+                context.Select(SceneGraph.SceneGraphFactory.FindNode(a.ID));
+                context.DeleteSelection();
+
+                return;
+            }
+
+            if (Presenter.Undo != null && Presenter.Undo.Enabled)
+            {
+                var thisActor = (Actor)Values[0];
+                var rootActor = thisActor.IsPrefabRoot ? thisActor : thisActor.GetPrefabRoot();
+                var prefabObjects = new List<object>();
+                GetAllPrefabObjects(prefabObjects, rootActor);
+                using (new UndoMultiBlock(Presenter.Undo, prefabObjects, "Revert to Prefab"))
+                {
+                    editor.RevertToReferenceValue();
+                    editor.RefreshInternal();
+                }
+            }
+            else
+            {
+                editor.RevertToReferenceValue();
+                editor.RefreshInternal();
+            }
         }
     }
 }

Source/Editor/CustomEditors/Dedicated/AudioSourceEditor.cs

@@ -13,6 +13,8 @@ namespace FlaxEditor.CustomEditors.Dedicated
     public class AudioSourceEditor : ActorEditor
     {
         private Label _infoLabel;
+        private Slider _slider;
+        private AudioSource.States _slideStartState;
 
         /// <inheritdoc />
         public override void Initialize(LayoutElementsContainer layout)
@@ -28,6 +30,13 @@ namespace FlaxEditor.CustomEditors.Dedicated
                 _infoLabel = playbackGroup.Label(string.Empty).Label;
                 _infoLabel.AutoHeight = true;
 
+                // Play back slider
+                var sliderElement = playbackGroup.CustomContainer<Slider>();
+                _slider = sliderElement.CustomControl;
+                _slider.ThumbSize = new Float2(_slider.ThumbSize.X * 0.5f, _slider.ThumbSize.Y);
+                _slider.SlidingStart += OnSlidingStart;
+                _slider.SlidingEnd += OnSlidingEnd;
+
                 var grid = playbackGroup.UniformGrid();
                 var gridControl = grid.CustomControl;
                 gridControl.ClipChildren = false;
@@ -40,6 +49,38 @@ namespace FlaxEditor.CustomEditors.Dedicated
             }
         }
 
+        private void OnSlidingEnd()
+        {
+            foreach (var value in Values)
+            {
+                if (value is AudioSource audioSource && audioSource.Clip)
+                {
+                    switch (_slideStartState)
+                    {
+                    case AudioSource.States.Playing:
+                        audioSource.Play();
+                        break;
+                    case AudioSource.States.Paused:
+                    case AudioSource.States.Stopped:
+                        audioSource.Pause();
+                        break;
+                    default: break;
+                    }
+                }
+            }
+        }
+
+        private void OnSlidingStart()
+        {
+            foreach (var value in Values)
+            {
+                if (value is AudioSource audioSource && audioSource.Clip)
+                {
+                    _slideStartState = audioSource.State;
+                }
+            }
+        }
+
         /// <inheritdoc />
         public override void Refresh()
         {
@@ -51,7 +92,29 @@ namespace FlaxEditor.CustomEditors.Dedicated
                 foreach (var value in Values)
                 {
                     if (value is AudioSource audioSource && audioSource.Clip)
+                    {
                         text += $"Time: {audioSource.Time:##0.0}s / {audioSource.Clip.Length:##0.0}s\n";
+                        _slider.Maximum = audioSource.Clip.Length;
+                        _slider.Minimum = 0;
+                        if (_slider.IsSliding)
+                        {
+                            if (audioSource.State != AudioSource.States.Playing)
+                            {
+                                // Play to move slider correctly
+                                audioSource.Play();
+                                audioSource.Time = _slider.Value;
+                            }
+                            else
+                            {
+                                audioSource.Time = _slider.Value;
+                            }
+                        }
+                        else
+                        {
+                            _slider.Value = audioSource.Time;
+                        }
+                        
+                    }
                 }
                 _infoLabel.Text = text;
             }

Source/Editor/CustomEditors/Dedicated/GPUTextureEditor.cs

@@ -0,0 +1,68 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+using FlaxEditor.GUI.ContextMenu;
+using FlaxEngine;
+using FlaxEngine.GUI;
+
+namespace FlaxEditor.CustomEditors.Dedicated
+{
+    /// <summary>
+    /// Basic editor/viewer for <see cref="GPUTexture"/>.
+    /// </summary>
+    [CustomEditor(typeof(GPUTexture)), DefaultEditor]
+    public class GPUTextureEditor : CustomEditor
+    {
+        private Image _image;
+
+        /// <inheritdoc />
+        public override DisplayStyle Style => DisplayStyle.Inline;
+
+        /// <inheritdoc />
+        public override void Initialize(LayoutElementsContainer layout)
+        {
+            _image = new Image
+            {
+                Brush = new GPUTextureBrush(),
+                Size = new Float2(200, 100),
+                Parent = layout.ContainerControl,
+            };
+            _image.Clicked += OnImageClicked;
+        }
+
+        private void OnImageClicked(Image image, MouseButton button)
+        {
+            var texture = Values[0] as GPUTexture;
+            if (!texture || button != MouseButton.Right)
+                return;
+            var menu = new ContextMenu();
+            menu.AddButton("Save...", () => Screenshot.Capture(Values[0] as GPUTexture));
+            menu.AddButton("Enlarge", () => _image.Size *= 2);
+            menu.AddButton("Shrink", () => _image.Size /= 2).Enabled = _image.Height > 32;
+            var location = image.PointFromScreen(Input.MouseScreenPosition);
+            menu.Show(image, location);
+        }
+
+        /// <inheritdoc />
+        public override void Refresh()
+        {
+            base.Refresh();
+
+            var texture = Values[0] as GPUTexture;
+            ((GPUTextureBrush)_image.Brush).Texture = texture;
+            if (texture)
+            {
+                var desc = texture.Description;
+#if BUILD_RELEASE
+                var name = string.Empty;
+#else
+                var name = texture.Name;
+#endif
+                _image.TooltipText = $"{name}\nType: {texture.ResourceType}\nSize: {desc.Width}x{desc.Height}\nFormat: {desc.Format}\nMemory: {Utilities.Utils.FormatBytesCount(texture.MemoryUsage)}";
+            }
+            else
+            {
+                _image.TooltipText = "None";
+            }
+        }
+    }
+}

Source/Editor/CustomEditors/Dedicated/LocalizationSettingsEditor.cs

@@ -190,12 +190,12 @@ namespace FlaxEditor.CustomEditors.Dedicated
                     foreach (var file in files)
                         FindNewKeysCSharp(file, newKeys, allKeys);
 
-                    // C++
-                    files = Directory.GetFiles(Globals.ProjectSourceFolder, "*.cpp", SearchOption.AllDirectories);
+                    // C/C++
+                    files = Directory.GetFiles(Globals.ProjectSourceFolder, "*.cpp", SearchOption.AllDirectories).Concat(Directory.GetFiles(Globals.ProjectSourceFolder, "*.c", SearchOption.AllDirectories)).ToArray();
                     filesCount += files.Length;
                     foreach (var file in files)
                         FindNewKeysCpp(file, newKeys, allKeys);
-                    files = Directory.GetFiles(Globals.ProjectSourceFolder, "*.h", SearchOption.AllDirectories);
+                    files = Directory.GetFiles(Globals.ProjectSourceFolder, "*.h", SearchOption.AllDirectories).Concat(Directory.GetFiles(Globals.ProjectSourceFolder, "*.hpp", SearchOption.AllDirectories)).ToArray();;
                     filesCount += files.Length;
                     foreach (var file in files)
                         FindNewKeysCpp(file, newKeys, allKeys);

Source/Editor/CustomEditors/Dedicated/ScriptsEditor.cs

@@ -36,6 +36,7 @@ namespace FlaxEditor.CustomEditors.Dedicated
         {
             ScriptName = scriptName;
             TooltipText = "Create a new script";
+            DrawHighlights = false;
         }
     }
 
@@ -70,7 +71,7 @@ namespace FlaxEditor.CustomEditors.Dedicated
             var buttonHeight = (textSize.Y < 18) ? 18 : textSize.Y + 4;
             _addScriptsButton = new Button
             {
-                TooltipText = "Add new scripts to the actor",
+                TooltipText = "Add new scripts to the actor.",
                 AnchorPreset = AnchorPresets.MiddleCenter,
                 Text = buttonText,
                 Parent = this,
@@ -114,7 +115,16 @@ namespace FlaxEditor.CustomEditors.Dedicated
             cm.TextChanged += text =>
             {
                 if (!IsValidScriptName(text))
+                {
+                    // Remove NewScriptItems
+                    List<Control> newScriptItems = cm.ItemsPanel.Children.FindAll(c => c is NewScriptItem);
+                    foreach (var item in newScriptItems)
+                    {
+                        cm.ItemsPanel.RemoveChild(item);
+                    }
+
                     return;
+                }
                 if (!cm.ItemsPanel.Children.Any(x => x.Visible && x is not NewScriptItem))
                 {
                     // If there are no visible items, that means the search failed so we can find the create script button or create one if it's the first time
@@ -876,7 +886,7 @@ namespace FlaxEditor.CustomEditors.Dedicated
                 // Add drag button to the group
                 var scriptDrag = new DragImage
                 {
-                    TooltipText = "Script reference",
+                    TooltipText = "Script reference.",
                     AutoFocus = true,
                     IsScrollable = false,
                     Color = FlaxEngine.GUI.Style.Current.ForegroundGrey,

Source/Editor/CustomEditors/Editors/ActorTransformEditor.cs

@@ -106,7 +106,6 @@ namespace FlaxEditor.CustomEditors.Editors
 
                 _linkButton = new Button
                 {
-                    BackgroundBrush = new SpriteBrush(Editor.Instance.Icons.Link32),
                     Parent = LinkedLabel,
                     Width = 18,
                     Height = 18,
@@ -189,6 +188,7 @@ namespace FlaxEditor.CustomEditors.Editors
                 _linkButton.SetColors(backgroundColor);
                 _linkButton.BorderColor = _linkButton.BorderColorSelected = _linkButton.BorderColorHighlighted = Color.Transparent;
                 _linkButton.TooltipText = LinkValues ? "Unlinks scale components from uniform scaling" : "Links scale components for uniform scaling";
+                _linkButton.BackgroundBrush = new SpriteBrush(LinkValues ? Editor.Instance.Icons.Link32 : Editor.Instance.Icons.BrokenLink32);
             }
         }
 

Source/Editor/CustomEditors/Editors/CollectionEditor.cs

@@ -70,7 +70,9 @@ namespace FlaxEditor.CustomEditors.Editors
                 menu.ItemsContainer.RemoveChildren();
 
                 menu.AddButton("Copy", linkedEditor.Copy);
-                var b = menu.AddButton("Paste", linkedEditor.Paste);
+                var b = menu.AddButton("Duplicate", () => Editor.Duplicate(Index));
+                b.Enabled = linkedEditor.CanPaste && !Editor._readOnly && Editor._canResize;
+                b = menu.AddButton("Paste", linkedEditor.Paste);
                 b.Enabled = linkedEditor.CanPaste && !Editor._readOnly;
 
                 menu.AddSeparator();
@@ -404,8 +406,10 @@ namespace FlaxEditor.CustomEditors.Editors
                 var menu = new ContextMenu();
 
                 menu.AddButton("Copy", linkedEditor.Copy);
+                var b = menu.AddButton("Duplicate", () => Editor.Duplicate(Index));
+                b.Enabled = linkedEditor.CanPaste && !Editor._readOnly && Editor._canResize;
                 var paste = menu.AddButton("Paste", linkedEditor.Paste);
-                paste.Enabled = linkedEditor.CanPaste;
+                paste.Enabled = linkedEditor.CanPaste && !Editor._readOnly;
 
                 if (_canReorder)
                 {
@@ -418,7 +422,8 @@ namespace FlaxEditor.CustomEditors.Editors
                     moveDownButton.Enabled = Index + 1 < Editor.Count;
                 }
 
-                menu.AddButton("Remove", OnRemoveClicked);
+                b = menu.AddButton("Remove", OnRemoveClicked);
+                b.Enabled = !Editor._readOnly && Editor._canResize;
 
                 menu.Show(panel, location);
             }
@@ -741,6 +746,34 @@ namespace FlaxEditor.CustomEditors.Editors
             cloned[srcIndex] = tmp;
             SetValue(cloned);
         }
+        
+        /// <summary>
+        /// Duplicates the list item.
+        /// </summary>
+        /// <param name="index">The index to duplicate.</param>
+        public void Duplicate(int index)
+        {
+            if (IsSetBlocked)
+                return;
+
+            var count = Count;
+            var newValues = Allocate(count + 1);
+            var oldValues = (IList)Values[0];
+   
+            for (int i = 0; i <= index; i++)
+            {
+                newValues[i] = oldValues[i];
+            }
+
+            newValues[index + 1] = Utilities.Utils.CloneValue(oldValues[index]);
+
+            for (int i = index + 1; i < count; i++)
+            {
+                newValues[i + 1] = oldValues[i];
+            }
+
+            SetValue(newValues);
+        }
 
         /// <summary>
         /// Shifts the specified item at the given index and moves it through the list to the other item. It supports undo.

Source/Editor/CustomEditors/Editors/ObjectSwitcherEditor.cs

@@ -3,6 +3,7 @@
 using System;
 using FlaxEditor.GUI;
 using FlaxEditor.Scripting;
+using FlaxEngine;
 using FlaxEngine.Utilities;
 
 namespace FlaxEditor.CustomEditors.Editors
@@ -81,9 +82,13 @@ namespace FlaxEditor.CustomEditors.Editors
 
         private OptionType[] _options;
         private ScriptType _type;
+        private Elements.PropertiesListElement _typeItem;
 
         private ScriptType Type => Values[0] == null ? Values.Type : TypeUtils.GetObjectType(Values[0]);
 
+        /// <inheritdoc />
+        public override bool RevertValueWithChildren => false; // Always revert value for a whole object
+
         /// <inheritdoc />
         public override void Initialize(LayoutElementsContainer layout)
         {
@@ -98,7 +103,8 @@ namespace FlaxEditor.CustomEditors.Editors
             _type = type;
 
             // Type
-            var typeEditor = layout.ComboBox(TypeComboBoxName, "Type of the object value. Use it to change the object.");
+            _typeItem = layout.AddPropertyItem(TypeComboBoxName, "Type of the object value. Use it to change the object.");
+            var typeEditor = _typeItem.ComboBox();
             for (int i = 0; i < _options.Length; i++)
             {
                 typeEditor.ComboBox.AddItem(_options[i].Name);
@@ -126,6 +132,8 @@ namespace FlaxEditor.CustomEditors.Editors
 
             // Value
             var values = new CustomValueContainer(type, (instance, index) => instance);
+            if (Values.HasReferenceValue)
+                values.SetReferenceValue(Values.ReferenceValue);
             values.AddRange(Values);
             var editor = CustomEditorsUtil.CreateEditor(type);
             var style = editor.Style;
@@ -170,6 +178,12 @@ namespace FlaxEditor.CustomEditors.Editors
         {
             base.Refresh();
 
+            // Show prefab diff when reference value type is different
+            var color = Color.Transparent;
+            if (Values.HasReferenceValue && CanRevertReferenceValue && Values[0]?.GetType() != Values.ReferenceValue?.GetType())
+                color = FlaxEngine.GUI.Style.Current.BackgroundSelected;
+            _typeItem.Labels[0].HighlightStripColor = color;
+
             // Check if type has been modified outside the editor (eg. from code)
             if (Type != _type)
             {

Source/Editor/CustomEditors/GUI/PropertiesList.cs

@@ -14,6 +14,9 @@ namespace FlaxEditor.CustomEditors.GUI
     public class PropertiesList : PanelWithMargins
     {
         // TODO: sync splitter for whole presenter
+       
+        private const float SplitterPadding = 15;
+        private const float EditorsMinWidthRatio = 0.4f;
 
         /// <summary>
         /// The splitter size (in pixels).
@@ -25,6 +28,7 @@ namespace FlaxEditor.CustomEditors.GUI
         private Rectangle _splitterRect;
         private bool _splitterClicked, _mouseOverSplitter;
         private bool _cursorChanged;
+        private bool _hasCustomSplitterValue;
 
         /// <summary>
         /// Gets or sets the splitter value (always in range [0; 1]).
@@ -66,6 +70,26 @@ namespace FlaxEditor.CustomEditors.GUI
             UpdateSplitRect();
         }
 
+        private void AutoSizeSplitter()
+        {
+            if (_hasCustomSplitterValue || !Editor.Instance.Options.Options.Interface.AutoSizePropertiesPanelSplitter)
+                return;
+
+            Font font = Style.Current.FontMedium;
+
+            float largestWidth = 0f;
+            for (int i = 0; i < _element.Labels.Count; i++)
+            {
+                Label currentLabel = _element.Labels[i];
+                Float2 dimensions = font.MeasureText(currentLabel.Text);
+                float width = dimensions.X + currentLabel.Margin.Left + SplitterPadding;
+
+                largestWidth = Mathf.Max(largestWidth, width);
+            }
+
+            SplitterValue = Mathf.Clamp(largestWidth / Width, 0, 1 - EditorsMinWidthRatio);
+        }
+
         private void UpdateSplitRect()
         {
             _splitterRect = new Rectangle(Mathf.Clamp(_splitterValue * Width - SplitterSize * 0.5f, 0.0f, Width), 0, SplitterSize, Height);
@@ -122,6 +146,7 @@ namespace FlaxEditor.CustomEditors.GUI
                 SplitterValue = location.X / Width;
                 Cursor = CursorType.SizeWE;
                 _cursorChanged = true;
+                _hasCustomSplitterValue = true;
             }
             else if (_mouseOverSplitter)
             {
@@ -195,6 +220,7 @@ namespace FlaxEditor.CustomEditors.GUI
             // Refresh
             UpdateSplitRect();
             PerformLayout(true);
+            AutoSizeSplitter();
         }
 
         /// <inheritdoc />

Source/Editor/Editor.cs

@@ -51,6 +51,7 @@ namespace FlaxEditor
         private readonly List<EditorModule> _modules = new List<EditorModule>(16);
         private bool _isAfterInit, _areModulesInited, _areModulesAfterInitEnd, _isHeadlessMode, _autoExit;
         private string _projectToOpen;
+        private bool _projectIsNew;
         private float _lastAutoSaveTimer, _autoExitTimeout = 0.1f;
         private Button _saveNowButton;
         private Button _cancelSaveButton;
@@ -528,7 +529,11 @@ namespace FlaxEditor
                 var timeSinceLastSave = Time.UnscaledGameTime - _lastAutoSaveTimer;
                 var timeToNextSave = options.AutoSaveFrequency * 60.0f - timeSinceLastSave;
 
-                if (timeToNextSave <= 0.0f || _autoSaveNow)
+                if (timeToNextSave <= 0.0f && GetWindows().Any(x => x.GUI.Children.Any(c => c is GUI.ContextMenu.ContextMenuBase)))
+                {
+                    // Skip aut-save if any context menu is opened to wait for user to end interaction
+                }
+                else if (timeToNextSave <= 0.0f || _autoSaveNow)
                 {
                     Log("Auto save");
                     _lastAutoSaveTimer = Time.UnscaledGameTime;
@@ -733,11 +738,12 @@ namespace FlaxEditor
                 var procSettings = new CreateProcessSettings
                 {
                     FileName = Platform.ExecutableFilePath,
-                    Arguments = string.Format("-project \"{0}\"", _projectToOpen),
+                    Arguments = string.Format("-project \"{0}\"" + (_projectIsNew ? " -new" : string.Empty), _projectToOpen),
                     ShellExecute = true,
                     WaitForEnd = false,
                     HiddenWindow = false,
                 };
+                _projectIsNew = false;
                 _projectToOpen = null;
                 Platform.CreateProcess(ref procSettings);
             }
@@ -786,6 +792,24 @@ namespace FlaxEditor
             }
         }
 
+        /// <summary>
+        /// Creates the given project. Afterwards closes this project with running editor and opens the given project.
+        /// </summary>
+        /// <param name="projectFilePath">The project file path.</param>
+        public void NewProject(string projectFilePath)
+        {
+            if (projectFilePath == null)
+            {
+                MessageBox.Show("Missing project");
+                return;
+            }
+
+            // Cache project path and start editor exit (it will open new instance on valid closing)
+            _projectToOpen = StringUtils.NormalizePath(Path.GetDirectoryName(projectFilePath));
+            _projectIsNew = true;
+            Windows.MainWindow.Close(ClosingReason.User);
+        }
+
         /// <summary>
         /// Closes this project with running editor and opens the given project.
         /// </summary>

Source/Editor/EditorIcons.cs

@@ -39,6 +39,7 @@ namespace FlaxEditor
         public SpriteHandle Globe32;
         public SpriteHandle CamSpeed32;
         public SpriteHandle Link32;
+        public SpriteHandle BrokenLink32;
         public SpriteHandle Add32;
         public SpriteHandle Left32;
         public SpriteHandle Right32;
@@ -94,6 +95,7 @@ namespace FlaxEditor
         public SpriteHandle Search64;
         public SpriteHandle Bone64;
         public SpriteHandle Link64;
+        public SpriteHandle BrokenLink64;
         public SpriteHandle Build64;
         public SpriteHandle Add64;
         public SpriteHandle ShipIt64;

Source/Editor/GUI/ContextMenu/ContextMenuBase.cs

@@ -1,7 +1,10 @@
-#if PLATFORM_WINDOWS
+#if PLATFORM_WINDOWS || PLATFORM_SDL
 #define USE_IS_FOREGROUND
 #else
 #endif
+#if PLATFORM_SDL
+#define USE_SDL_WORKAROUNDS
+#endif
 // Copyright (c) Wojciech Figat. All rights reserved.
 
 using System.Collections.Generic;
@@ -121,7 +124,7 @@ namespace FlaxEditor.GUI.ContextMenu
         }
 
         /// <summary>
-        /// Shows the empty menu popup o na screen.
+        /// Shows the empty menu popup on a screen.
         /// </summary>
         /// <param name="control">The target control.</param>
         /// <param name="area">The target control area to cover.</param>
@@ -256,7 +259,9 @@ namespace FlaxEditor.GUI.ContextMenu
                 desc.AllowMaximize = false;
                 desc.AllowDragAndDrop = false;
                 desc.IsTopmost = true;
-                desc.IsRegularWindow = false;
+                desc.Type = WindowType.Popup;
+                desc.Parent = parentWin.Window;
+                desc.Title = "ContextMenu";
                 desc.HasSizingFrame = false;
                 OnWindowCreating(ref desc);
                 _window = Platform.CreateWindow(ref desc);
@@ -265,6 +270,12 @@ namespace FlaxEditor.GUI.ContextMenu
                     _window.GotFocus += OnWindowGotFocus;
                     _window.LostFocus += OnWindowLostFocus;
                 }
+                
+#if USE_IS_FOREGROUND && USE_SDL_WORKAROUNDS
+                // The focus between popup and parent windows doesn't change, force hide the popup when clicked on parent
+                parentWin.Window.MouseDown += OnWindowMouseDown;
+                _window.Closed += () => parentWin.Window.MouseDown -= OnWindowMouseDown;
+#endif
 
                 // Attach to the window
                 _parentCM = parent as ContextMenuBase;
@@ -440,6 +451,17 @@ namespace FlaxEditor.GUI.ContextMenu
             }
         }
 
+#if USE_SDL_WORKAROUNDS
+        private void OnWindowGotFocus()
+        {
+        }
+        
+        private void OnWindowMouseDown(ref Float2 mousePosition, MouseButton button, ref bool handled)
+        {
+            // The user clicked outside the popup window
+            Hide();
+        }
+#else
         private void OnWindowGotFocus()
         {
             var child = _childCM;
@@ -453,6 +475,7 @@ namespace FlaxEditor.GUI.ContextMenu
                 });
             }
         }
+#endif
 
         private void OnWindowLostFocus()
         {
@@ -551,7 +574,12 @@ namespace FlaxEditor.GUI.ContextMenu
             // Let root context menu to check if none of the popup windows
             if (_parentCM == null && UseVisibilityControl && !IsForeground)
             {
+#if USE_SDL_WORKAROUNDS
+                if (!IsMouseOver)
+                    Hide();
+#else
                 Hide();
+#endif
             }
         }
 #endif

Source/Editor/GUI/Dialogs/ColorPickerDialog.cs

@@ -326,8 +326,11 @@ namespace FlaxEditor.GUI.Dialogs
             // Update eye dropper tool
             if (_activeEyedropper)
             {
+                // Try reading the color under the cursor in realtime if supported by the platform
                 Float2 mousePosition = Platform.MousePosition;
-                SelectedColor = ScreenUtilities.GetColorAt(mousePosition);
+                Color color = ScreenUtilities.GetColorAt(mousePosition);
+                if (color != Color.Transparent)
+                    SelectedColor = color;
             }
         }
 

Source/Editor/GUI/Docking/DockHintWindow.cs

@@ -1,545 +0,0 @@
-// Copyright (c) Wojciech Figat. All rights reserved.
-
-using System;
-using FlaxEngine;
-using FlaxEngine.GUI;
-
-namespace FlaxEditor.GUI.Docking
-{
-    /// <summary>
-    /// Helper class used to handle docking windows dragging and docking.
-    /// </summary>
-    public class DockHintWindow
-    {
-        private FloatWindowDockPanel _toMove;
-
-        private Float2 _dragOffset;
-        private Float2 _defaultWindowSize;
-        private Rectangle _rectDock;
-        private Rectangle _rectWindow;
-        private Float2 _mouse;
-        private DockState _toSet;
-        private DockPanel _toDock;
-        private bool _lateDragOffsetUpdate;
-
-        private Rectangle _rLeft, _rRight, _rBottom, _rUpper, _rCenter;
-
-        private DockHintWindow(FloatWindowDockPanel toMove)
-        {
-            _toMove = toMove;
-            _toSet = DockState.Float;
-            var window = toMove.Window.Window;
-
-            // Remove focus from drag target
-            _toMove.Focus();
-            _toMove.Defocus();
-
-            // Focus window
-            window.Focus();
-
-            // Check if window is maximized and restore window.
-            if (window.IsMaximized)
-            {
-                // Restore window and set position to mouse.
-                var mousePos = window.MousePosition;
-                var previousSize = window.Size;
-                window.Restore();
-                window.Position = Platform.MousePosition - mousePos * window.Size / previousSize;
-            }
-
-            // Calculate dragging offset and move window to the destination position
-            var mouseScreenPosition = Platform.MousePosition;
-
-            // If the _toMove window was not focused when initializing this window, the result vector only contains zeros
-            // and to prevent a failure, we need to perform an update for the drag offset at later time which will be done in the OnMouseMove event handler.
-            if (mouseScreenPosition != Float2.Zero)
-                CalculateDragOffset(mouseScreenPosition);
-            else
-                _lateDragOffsetUpdate = true;
-
-            // Get initial size
-            _defaultWindowSize = window.Size;
-
-            // Init proxy window
-            Proxy.Init(ref _defaultWindowSize);
-
-            // Bind events
-            Proxy.Window.MouseUp += OnMouseUp;
-            Proxy.Window.MouseMove += OnMouseMove;
-            Proxy.Window.LostFocus += OnLostFocus;
-
-            // Start tracking mouse
-            Proxy.Window.StartTrackingMouse(false);
-
-            // Update window GUI
-            Proxy.Window.GUI.PerformLayout();
-
-            // Update rectangles
-            UpdateRects();
-
-            // Hide base window
-            window.Hide();
-
-            // Enable hit window presentation
-            Proxy.Window.RenderingEnabled = true;
-            Proxy.Window.Show();
-            Proxy.Window.Focus();
-        }
-
-        /// <summary>
-        /// Releases unmanaged and - optionally - managed resources.
-        /// </summary>
-        public void Dispose()
-        {
-            // End tracking mouse
-            Proxy.Window.EndTrackingMouse();
-
-            // Disable rendering
-            Proxy.Window.RenderingEnabled = false;
-
-            // Unbind events
-            Proxy.Window.MouseUp -= OnMouseUp;
-            Proxy.Window.MouseMove -= OnMouseMove;
-            Proxy.Window.LostFocus -= OnLostFocus;
-
-            // Hide the proxy
-            Proxy.Hide();
-
-            if (_toMove == null)
-                return;
-
-            // Check if window won't be docked
-            if (_toSet == DockState.Float)
-            {
-                var window = _toMove.Window?.Window;
-                if (window == null)
-                    return;
-                var mouse = Platform.MousePosition;
-
-                // Move base window
-                window.Position = mouse - _dragOffset;
-
-                // Show base window
-                window.Show();
-            }
-            else
-            {
-                bool hasNoChildPanels = _toMove.ChildPanelsCount == 0;
-
-                // Check if window has only single tab
-                if (hasNoChildPanels && _toMove.TabsCount == 1)
-                {
-                    // Dock window
-                    _toMove.GetTab(0).Show(_toSet, _toDock);
-                }
-                // Check if dock as tab and has no child panels
-                else if (hasNoChildPanels && _toSet == DockState.DockFill)
-                {
-                    // Dock all tabs
-                    while (_toMove.TabsCount > 0)
-                    {
-                        _toMove.GetTab(0).Show(DockState.DockFill, _toDock);
-                    }
-                }
-                else
-                {
-                    var selectedTab = _toMove.SelectedTab;
-
-                    // Dock the first tab into the target location
-                    var firstTab = _toMove.GetTab(0);
-                    firstTab.Show(_toSet, _toDock);
-
-                    // Dock rest of the tabs
-                    while (_toMove.TabsCount > 0)
-                    {
-                        _toMove.GetTab(0).Show(DockState.DockFill, firstTab);
-                    }
-
-                    // Keep selected tab being selected
-                    selectedTab?.SelectTab();
-                }
-
-                // Focus target window
-                _toDock.Root.Focus();
-            }
-
-            _toMove = null;
-        }
-
-        /// <summary>
-        /// Creates the new dragging hit window.
-        /// </summary>
-        /// <param name="toMove">Floating dock panel to move.</param>
-        /// <returns>The dock hint window object.</returns>
-        public static DockHintWindow Create(FloatWindowDockPanel toMove)
-        {
-            if (toMove == null)
-                throw new ArgumentNullException();
-
-            return new DockHintWindow(toMove);
-        }
-
-        /// <summary>
-        /// Creates the new dragging hit window.
-        /// </summary>
-        /// <param name="toMove">Dock window to move.</param>
-        /// <returns>The dock hint window object.</returns>
-        public static DockHintWindow Create(DockWindow toMove)
-        {
-            if (toMove == null)
-                throw new ArgumentNullException();
-
-            // Show floating
-            toMove.ShowFloating();
-
-            // Move window to the mouse position (with some offset for caption bar)
-            var window = (WindowRootControl)toMove.Root;
-            var mouse = Platform.MousePosition;
-            window.Window.Position = mouse - new Float2(8, 8);
-
-            // Get floating panel
-            var floatingPanelToMove = window.GetChild(0) as FloatWindowDockPanel;
-
-            return new DockHintWindow(floatingPanelToMove);
-        }
-
-        /// <summary>
-        /// Calculates window rectangle in the dock window.
-        /// </summary>
-        /// <param name="state">Window dock state.</param>
-        /// <param name="rect">Dock panel rectangle.</param>
-        /// <returns>Calculated window rectangle.</returns>
-        public static Rectangle CalculateDockRect(DockState state, ref Rectangle rect)
-        {
-            Rectangle result = rect;
-            switch (state)
-            {
-            case DockState.DockFill:
-                result.Location.Y += DockPanel.DefaultHeaderHeight;
-                result.Size.Y -= DockPanel.DefaultHeaderHeight;
-                break;
-            case DockState.DockTop:
-                result.Size.Y *= DockPanel.DefaultSplitterValue;
-                break;
-            case DockState.DockLeft:
-                result.Size.X *= DockPanel.DefaultSplitterValue;
-                break;
-            case DockState.DockBottom:
-                result.Location.Y += result.Size.Y * (1 - DockPanel.DefaultSplitterValue);
-                result.Size.Y *= DockPanel.DefaultSplitterValue;
-                break;
-            case DockState.DockRight:
-                result.Location.X += result.Size.X * (1 - DockPanel.DefaultSplitterValue);
-                result.Size.X *= DockPanel.DefaultSplitterValue;
-                break;
-            }
-            return result;
-        }
-
-        private void CalculateDragOffset(Float2 mouseScreenPosition)
-        {
-            var baseWinPos = _toMove.Window.Window.Position;
-            _dragOffset = mouseScreenPosition - baseWinPos;
-        }
-
-        private void UpdateRects()
-        {
-            // Cache mouse position
-            _mouse = Platform.MousePosition;
-
-            // Check intersection with any dock panel
-            var uiMouse = _mouse;
-            _toDock = _toMove.MasterPanel.HitTest(ref uiMouse, _toMove);
-
-            // Check dock state to use
-            bool showProxyHints = _toDock != null;
-            bool showBorderHints = showProxyHints;
-            bool showCenterHint = showProxyHints;
-            if (showProxyHints)
-            {
-                // If moved window has not only tabs but also child panels disable docking as tab
-                if (_toMove.ChildPanelsCount > 0)
-                    showCenterHint = false;
-
-                // Disable docking windows with one or more dock panels inside
-                if (_toMove.ChildPanelsCount > 0)
-                    showBorderHints = false;
-
-                // Get dock area
-                _rectDock = _toDock.DockAreaBounds;
-
-                // Cache dock rectangles
-                var size = _rectDock.Size;
-                var offset = _rectDock.Location;
-                var borderMargin = 4.0f;
-                var hintWindowsSize = Proxy.HintWindowsSize * Platform.DpiScale;
-                var hintWindowsSize2 = hintWindowsSize * 0.5f;
-                var centerX = size.X * 0.5f;
-                var centerY = size.Y * 0.5f;
-                _rUpper = new Rectangle(centerX - hintWindowsSize2, borderMargin, hintWindowsSize, hintWindowsSize) + offset;
-                _rBottom = new Rectangle(centerX - hintWindowsSize2, size.Y - hintWindowsSize - borderMargin, hintWindowsSize, hintWindowsSize) + offset;
-                _rLeft = new Rectangle(borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
-                _rRight = new Rectangle(size.X - hintWindowsSize - borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
-                _rCenter = new Rectangle(centerX - hintWindowsSize2, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
-
-                // Hit test
-                DockState toSet = DockState.Float;
-                if (showBorderHints)
-                {
-                    if (_rUpper.Contains(_mouse))
-                        toSet = DockState.DockTop;
-                    else if (_rBottom.Contains(_mouse))
-                        toSet = DockState.DockBottom;
-                    else if (_rLeft.Contains(_mouse))
-                        toSet = DockState.DockLeft;
-                    else if (_rRight.Contains(_mouse))
-                        toSet = DockState.DockRight;
-                }
-                if (showCenterHint && _rCenter.Contains(_mouse))
-                    toSet = DockState.DockFill;
-                _toSet = toSet;
-
-                // Show proxy hint windows
-                Proxy.Down.Position = _rBottom.Location;
-                Proxy.Left.Position = _rLeft.Location;
-                Proxy.Right.Position = _rRight.Location;
-                Proxy.Up.Position = _rUpper.Location;
-                Proxy.Center.Position = _rCenter.Location;
-            }
-            else
-            {
-                _toSet = DockState.Float;
-            }
-
-            // Update proxy hint windows visibility
-            Proxy.Down.IsVisible = showProxyHints & showBorderHints;
-            Proxy.Left.IsVisible = showProxyHints & showBorderHints;
-            Proxy.Right.IsVisible = showProxyHints & showBorderHints;
-            Proxy.Up.IsVisible = showProxyHints & showBorderHints;
-            Proxy.Center.IsVisible = showProxyHints & showCenterHint;
-
-            // Calculate proxy/dock/window rectangles
-            if (_toDock == null)
-            {
-                // Floating window over nothing
-                _rectWindow = new Rectangle(_mouse - _dragOffset, _defaultWindowSize);
-            }
-            else
-            {
-                if (_toSet == DockState.Float)
-                {
-                    // Floating window over dock panel
-                    _rectWindow = new Rectangle(_mouse - _dragOffset, _defaultWindowSize);
-                }
-                else
-                {
-                    // Use only part of the dock panel to show hint
-                    _rectWindow = CalculateDockRect(_toSet, ref _rectDock);
-                }
-            }
-
-            // Update proxy window
-            Proxy.Window.ClientBounds = _rectWindow;
-        }
-
-        private void OnMouseUp(ref Float2 location, MouseButton button, ref bool handled)
-        {
-            if (button == MouseButton.Left)
-            {
-                Dispose();
-            }
-        }
-
-        private void OnMouseMove(ref Float2 mousePos)
-        {
-            // Recalculate the drag offset because the current mouse screen position was invalid when we initialized the window
-            if (_lateDragOffsetUpdate)
-            {
-                // Calculate dragging offset and move window to the destination position
-                CalculateDragOffset(mousePos);
-
-                // Reset state
-                _lateDragOffsetUpdate = false;
-            }
-
-            UpdateRects();
-        }
-
-        private void OnLostFocus()
-        {
-            Dispose();
-        }
-
-        /// <summary>
-        /// Contains helper proxy windows shared across docking panels. They are used to visualize docking window locations.
-        /// </summary>
-        public static class Proxy
-        {
-            /// <summary>
-            /// The drag proxy window.
-            /// </summary>
-            public static Window Window;
-
-            /// <summary>
-            /// The left hint proxy window.
-            /// </summary>
-            public static Window Left;
-
-            /// <summary>
-            /// The right hint proxy window.
-            /// </summary>
-            public static Window Right;
-
-            /// <summary>
-            /// The up hint proxy window.
-            /// </summary>
-            public static Window Up;
-
-            /// <summary>
-            /// The down hint proxy window.
-            /// </summary>
-            public static Window Down;
-
-            /// <summary>
-            /// The center hint proxy window.
-            /// </summary>
-            public static Window Center;
-
-            /// <summary>
-            /// The hint windows size.
-            /// </summary>
-            public const float HintWindowsSize = 32.0f;
-
-            /// <summary>
-            /// Initializes the hit proxy windows. Those windows are used to indicate drag target areas (left, right, top, bottom, etc.).
-            /// </summary>
-            public static void InitHitProxy()
-            {
-                CreateProxy(ref Left, "DockHint.Left");
-                CreateProxy(ref Right, "DockHint.Right");
-                CreateProxy(ref Up, "DockHint.Up");
-                CreateProxy(ref Down, "DockHint.Down");
-                CreateProxy(ref Center, "DockHint.Center");
-            }
-
-            /// <summary>
-            /// Initializes the hint window.
-            /// </summary>
-            /// <param name="initSize">Initial size of the proxy window.</param>
-            public static void Init(ref Float2 initSize)
-            {
-                if (Window == null)
-                {
-                    var settings = CreateWindowSettings.Default;
-                    settings.Title = "DockHint.Window";
-                    settings.Size = initSize;
-                    settings.AllowInput = true;
-                    settings.AllowMaximize = false;
-                    settings.AllowMinimize = false;
-                    settings.HasBorder = false;
-                    settings.HasSizingFrame = false;
-                    settings.IsRegularWindow = false;
-                    settings.SupportsTransparency = true;
-                    settings.ShowInTaskbar = false;
-                    settings.ShowAfterFirstPaint = false;
-                    settings.IsTopmost = true;
-
-                    Window = Platform.CreateWindow(ref settings);
-                    Window.Opacity = 0.6f;
-                    Window.GUI.BackgroundColor = Style.Current.Selection;
-                    Window.GUI.AddChild<DragVisuals>();
-                }
-                else
-                {
-                    // Resize proxy
-                    Window.ClientSize = initSize;
-                }
-
-                InitHitProxy();
-            }
-
-            private sealed class DragVisuals : Control
-            {
-                public DragVisuals()
-                {
-                    AnchorPreset = AnchorPresets.StretchAll;
-                    Offsets = Margin.Zero;
-                }
-
-                public override void Draw()
-                {
-                    Render2D.DrawRectangle(new Rectangle(Float2.Zero, Size), Style.Current.SelectionBorder);
-                }
-            }
-
-            private static void CreateProxy(ref Window win, string name)
-            {
-                if (win != null)
-                    return;
-
-                var settings = CreateWindowSettings.Default;
-                settings.Title = name;
-                settings.Size = new Float2(HintWindowsSize * Platform.DpiScale);
-                settings.AllowInput = false;
-                settings.AllowMaximize = false;
-                settings.AllowMinimize = false;
-                settings.HasBorder = false;
-                settings.HasSizingFrame = false;
-                settings.IsRegularWindow = false;
-                settings.SupportsTransparency = true;
-                settings.ShowInTaskbar = false;
-                settings.ActivateWhenFirstShown = false;
-                settings.IsTopmost = true;
-                settings.ShowAfterFirstPaint = false;
-
-                win = Platform.CreateWindow(ref settings);
-                win.Opacity = 0.6f;
-                win.GUI.BackgroundColor = Style.Current.Selection;
-                win.GUI.AddChild<DragVisuals>();
-            }
-
-            /// <summary>
-            /// Hides proxy windows.
-            /// </summary>
-            public static void Hide()
-            {
-                HideProxy(ref Window);
-                HideProxy(ref Left);
-                HideProxy(ref Right);
-                HideProxy(ref Up);
-                HideProxy(ref Down);
-                HideProxy(ref Center);
-            }
-
-            private static void HideProxy(ref Window win)
-            {
-                if (win)
-                {
-                    win.Hide();
-                }
-            }
-
-            /// <summary>
-            /// Releases proxy data and windows.
-            /// </summary>
-            public static void Dispose()
-            {
-                DisposeProxy(ref Window);
-                DisposeProxy(ref Left);
-                DisposeProxy(ref Right);
-                DisposeProxy(ref Up);
-                DisposeProxy(ref Down);
-                DisposeProxy(ref Center);
-            }
-
-            private static void DisposeProxy(ref Window win)
-            {
-                if (win)
-                {
-                    win.Close(ClosingReason.User);
-                    win = null;
-                }
-            }
-        }
-    }
-}

Source/Editor/GUI/Docking/DockPanelProxy.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Wojciech Figat. All rights reserved.
 
 using FlaxEditor.GUI.ContextMenu;
+using FlaxEditor.Options;
 using FlaxEngine;
 using FlaxEngine.GUI;
 
@@ -13,12 +14,12 @@ namespace FlaxEditor.GUI.Docking
     public class DockPanelProxy : ContainerControl
     {
         private DockPanel _panel;
+        private InterfaceOptions.TabCloseButtonVisibility closeButtonVisibility;
         private double _dragEnterTime = -1;
-    #if PLATFORM_WINDOWS
-        private const bool HideTabForSingleTab = true;
-    #else
-        private const bool HideTabForSingleTab = false;
-    #endif
+        private float _tabHeight = Editor.Instance.Options.Options.Interface.TabHeight;
+        private bool _useMinimumTabWidth = Editor.Instance.Options.Options.Interface.UseMinimumTabWidth;
+        private float _minimumTabWidth = Editor.Instance.Options.Options.Interface.MinimumTabWidth;
+        private readonly bool _hideTabForSingleTab = Utilities.Utils.HideSingleTabWindowTabBars();
 
         /// <summary>
         /// The is mouse down flag (left button).
@@ -49,14 +50,19 @@ namespace FlaxEditor.GUI.Docking
         /// The mouse position.
         /// </summary>
         public Float2 MousePosition = Float2.Minimum;
+        
+        /// <summary>
+        /// The mouse position.
+        /// </summary>
+        public Float2 MouseStartPosition = Float2.Minimum;
 
         /// <summary>
         /// The start drag asynchronous window.
         /// </summary>
         public DockWindow StartDragAsyncWindow;
 
-        private Rectangle HeaderRectangle => new Rectangle(0, 0, Width, DockPanel.DefaultHeaderHeight);
-        private bool IsSingleFloatingWindow => HideTabForSingleTab && _panel.TabsCount == 1 && _panel.IsFloating && _panel.ChildPanelsCount == 0;
+        private Rectangle HeaderRectangle => new Rectangle(0, 0, Width, _tabHeight);
+        private bool IsSingleFloatingWindow => _hideTabForSingleTab && _panel.TabsCount == 1 && _panel.IsFloating && _panel.ChildPanelsCount == 0;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="DockPanelProxy"/> class.
@@ -70,6 +76,14 @@ namespace FlaxEditor.GUI.Docking
             _panel = panel;
             AnchorPreset = AnchorPresets.StretchAll;
             Offsets = Margin.Zero;
+
+            Editor.Instance.Options.OptionsChanged += OnEditorOptionsChanged;
+            OnEditorOptionsChanged(Editor.Instance.Options.Options);
+        }
+
+        private void OnEditorOptionsChanged(EditorOptions options)
+        {
+            closeButtonVisibility = options.Interface.ShowTabCloseButton;
         }
 
         private DockWindow GetTabAtPos(Float2 position, out bool closeButton)
@@ -80,11 +94,11 @@ namespace FlaxEditor.GUI.Docking
             var tabsCount = _panel.TabsCount;
             if (tabsCount == 1)
             {
-                var crossRect = new Rectangle(Width - DockPanel.DefaultButtonsSize - DockPanel.DefaultButtonsMargin, (DockPanel.DefaultHeaderHeight - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize);
+                var crossRect = new Rectangle(Width - DockPanel.DefaultButtonsSize - DockPanel.DefaultButtonsMargin, (HeaderRectangle.Height - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize);
                 if (HeaderRectangle.Contains(position))
                 {
-                    closeButton = crossRect.Contains(position);
                     result = _panel.GetTab(0);
+                    closeButton = crossRect.Contains(position) && IsCloseButtonVisible(result, closeButtonVisibility);
                 }
             }
             else
@@ -93,15 +107,17 @@ namespace FlaxEditor.GUI.Docking
                 for (int i = 0; i < tabsCount; i++)
                 {
                     var tab = _panel.GetTab(i);
-                    var titleSize = tab.TitleSize;
-                    var iconWidth = tab.Icon.IsValid ? DockPanel.DefaultButtonsSize + DockPanel.DefaultLeftTextMargin : 0;
-                    var width = titleSize.X + DockPanel.DefaultButtonsSize + 2 * DockPanel.DefaultButtonsMargin + DockPanel.DefaultLeftTextMargin + DockPanel.DefaultRightTextMargin + iconWidth;
-                    var tabRect = new Rectangle(x, 0, width, DockPanel.DefaultHeaderHeight);
+                    float width = CalculateTabWidth(tab, closeButtonVisibility);
+
+                    if (_useMinimumTabWidth && width < _minimumTabWidth)
+                        width = _minimumTabWidth;
+
+                    var tabRect = new Rectangle(x, 0, width, HeaderRectangle.Height);
                     var isMouseOver = tabRect.Contains(position);
                     if (isMouseOver)
                     {
-                        var crossRect = new Rectangle(x + width - DockPanel.DefaultButtonsSize - DockPanel.DefaultButtonsMargin, (DockPanel.DefaultHeaderHeight - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize);
-                        closeButton = crossRect.Contains(position);
+                        var crossRect = new Rectangle(x + width - DockPanel.DefaultButtonsSize - DockPanel.DefaultButtonsMargin, (HeaderRectangle.Height - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize);
+                        closeButton = crossRect.Contains(position) && IsCloseButtonVisible(tab, closeButtonVisibility);
                         result = tab;
                         break;
                     }
@@ -112,6 +128,24 @@ namespace FlaxEditor.GUI.Docking
             return result;
         }
 
+        private bool IsCloseButtonVisible(DockWindow win, InterfaceOptions.TabCloseButtonVisibility visibilityMode)
+        {
+            return visibilityMode != InterfaceOptions.TabCloseButtonVisibility.Never &&
+                (visibilityMode == InterfaceOptions.TabCloseButtonVisibility.Always ||
+                (visibilityMode == InterfaceOptions.TabCloseButtonVisibility.SelectedTab && _panel.SelectedTab == win));
+        }
+
+        private float CalculateTabWidth(DockWindow win, InterfaceOptions.TabCloseButtonVisibility visibilityMode)
+        {
+            var iconWidth = win.Icon.IsValid ? DockPanel.DefaultButtonsSize + DockPanel.DefaultLeftTextMargin : 0;
+            var width = win.TitleSize.X + DockPanel.DefaultLeftTextMargin + DockPanel.DefaultRightTextMargin + iconWidth;
+
+            if (IsCloseButtonVisible(win, visibilityMode))
+                width += 2 * DockPanel.DefaultButtonsMargin + DockPanel.DefaultButtonsSize;
+
+            return width;
+        }
+
         private void GetTabRect(DockWindow win, out Rectangle bounds)
         {
             FlaxEngine.Assertions.Assert.IsTrue(_panel.ContainsTab(win));
@@ -129,10 +163,10 @@ namespace FlaxEditor.GUI.Docking
                 {
                     var tab = _panel.GetTab(i);
                     var titleSize = tab.TitleSize;
-                    float width = titleSize.X + DockPanel.DefaultButtonsSize + 2 * DockPanel.DefaultButtonsMargin + DockPanel.DefaultLeftTextMargin + DockPanel.DefaultRightTextMargin;
+                    float width = CalculateTabWidth(tab, closeButtonVisibility);
                     if (tab == win)
                     {
-                        bounds = new Rectangle(x, 0, width, DockPanel.DefaultHeaderHeight);
+                        bounds = new Rectangle(x, 0, width, HeaderRectangle.Height);
                         return;
                     }
                     x += width;
@@ -165,7 +199,7 @@ namespace FlaxEditor.GUI.Docking
                 if (_panel.ChildPanelsCount == 0 && _panel.TabsCount == 1 && _panel.IsFloating)
                 {
                     // Create docking hint window but in an async manner
-                    DockHintWindow.Create(_panel as FloatWindowDockPanel);
+                    WindowDragHelper.StartDragging(_panel as FloatWindowDockPanel);
                 }
                 else
                 {
@@ -176,7 +210,7 @@ namespace FlaxEditor.GUI.Docking
                     _panel.SelectTab(index - 1);
 
                     // Create docking hint window
-                    DockHintWindow.Create(win);
+                    WindowDragHelper.StartDragging(win, _panel.RootWindow.Window);
                 }
             }
         }
@@ -212,7 +246,7 @@ namespace FlaxEditor.GUI.Docking
                 {
                     Render2D.DrawSprite(
                         tab.Icon,
-                        new Rectangle(DockPanel.DefaultLeftTextMargin, (DockPanel.DefaultHeaderHeight - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize),
+                        new Rectangle(DockPanel.DefaultLeftTextMargin, (HeaderRectangle.Height - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize),
                         style.Foreground);
 
                 }
@@ -221,17 +255,20 @@ namespace FlaxEditor.GUI.Docking
                 Render2D.DrawText(
                     style.FontMedium,
                     tab.Title,
-                    new Rectangle(DockPanel.DefaultLeftTextMargin + iconWidth, 0, Width - DockPanel.DefaultLeftTextMargin - DockPanel.DefaultButtonsSize - 2 * DockPanel.DefaultButtonsMargin, DockPanel.DefaultHeaderHeight),
+                    new Rectangle(DockPanel.DefaultLeftTextMargin + iconWidth, 0, Width - DockPanel.DefaultLeftTextMargin - DockPanel.DefaultButtonsSize - 2 * DockPanel.DefaultButtonsMargin, HeaderRectangle.Height),
                     style.Foreground,
                     TextAlignment.Near,
                     TextAlignment.Center);
 
-                // Draw cross
-                var crossRect = new Rectangle(Width - DockPanel.DefaultButtonsSize - DockPanel.DefaultButtonsMargin, (DockPanel.DefaultHeaderHeight - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize);
-                bool isMouseOverCross = isMouseOver && crossRect.Contains(MousePosition);
-                if (isMouseOverCross)
-                    Render2D.FillRectangle(crossRect, (containsFocus ? style.BackgroundSelected : style.LightBackground) * 1.3f);
-                Render2D.DrawSprite(style.Cross, crossRect, isMouseOverCross ? style.Foreground : style.ForegroundGrey);
+                if (IsCloseButtonVisible(tab, closeButtonVisibility))
+                {
+                    // Draw cross
+                    var crossRect = new Rectangle(Width - DockPanel.DefaultButtonsSize - DockPanel.DefaultButtonsMargin, (HeaderRectangle.Height - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize);
+                    bool isMouseOverCross = isMouseOver && crossRect.Contains(MousePosition);
+                    if (isMouseOverCross)
+                        Render2D.FillRectangle(crossRect, (containsFocus ? style.BackgroundSelected : style.LightBackground) * 1.3f);
+                    Render2D.DrawSprite(style.Cross, crossRect, isMouseOverCross ? style.Foreground : style.ForegroundGrey);
+                }
             }
             else
             {
@@ -245,10 +282,14 @@ namespace FlaxEditor.GUI.Docking
                     // Cache data
                     var tab = _panel.GetTab(i);
                     var tabColor = Color.Black;
-                    var titleSize = tab.TitleSize;
                     var iconWidth = tab.Icon.IsValid ? DockPanel.DefaultButtonsSize + DockPanel.DefaultLeftTextMargin : 0;
-                    var width = titleSize.X + DockPanel.DefaultButtonsSize + 2 * DockPanel.DefaultButtonsMargin + DockPanel.DefaultLeftTextMargin + DockPanel.DefaultRightTextMargin + iconWidth;
-                    var tabRect = new Rectangle(x, 0, width, DockPanel.DefaultHeaderHeight);
+
+                    float width = CalculateTabWidth(tab, closeButtonVisibility);
+
+                    if (_useMinimumTabWidth && width < _minimumTabWidth)
+                        width = _minimumTabWidth;
+
+                    var tabRect = new Rectangle(x, 0, width, headerRect.Height);
                     var isMouseOver = tabRect.Contains(MousePosition);
                     var isSelected = _panel.SelectedTab == tab;
 
@@ -275,7 +316,7 @@ namespace FlaxEditor.GUI.Docking
                     {
                         Render2D.DrawSprite(
                             tab.Icon,
-                            new Rectangle(x + DockPanel.DefaultLeftTextMargin, (DockPanel.DefaultHeaderHeight - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize),
+                            new Rectangle(x + DockPanel.DefaultLeftTextMargin, (HeaderRectangle.Height - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize),
                             style.Foreground);
 
                     }
@@ -284,27 +325,27 @@ namespace FlaxEditor.GUI.Docking
                     Render2D.DrawText(
                         style.FontMedium,
                         tab.Title,
-                        new Rectangle(x + DockPanel.DefaultLeftTextMargin + iconWidth, 0, 10000, DockPanel.DefaultHeaderHeight),
+                        new Rectangle(x + DockPanel.DefaultLeftTextMargin + iconWidth, 0, 10000, HeaderRectangle.Height),
                         style.Foreground,
                         TextAlignment.Near,
                         TextAlignment.Center);
 
                     // Draw cross
-                    if (isSelected || isMouseOver)
+                    if (IsCloseButtonVisible(tab, closeButtonVisibility))
                     {
-                        var crossRect = new Rectangle(x + width - DockPanel.DefaultButtonsSize - DockPanel.DefaultButtonsMargin, (DockPanel.DefaultHeaderHeight - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize);
+                        var crossRect = new Rectangle(x + width - DockPanel.DefaultButtonsSize - DockPanel.DefaultButtonsMargin, (HeaderRectangle.Height - DockPanel.DefaultButtonsSize) / 2, DockPanel.DefaultButtonsSize, DockPanel.DefaultButtonsSize);
                         bool isMouseOverCross = isMouseOver && crossRect.Contains(MousePosition);
                         if (isMouseOverCross)
                             Render2D.FillRectangle(crossRect, tabColor * 1.3f);
                         Render2D.DrawSprite(style.Cross, crossRect, isMouseOverCross ? style.Foreground : style.ForegroundGrey);
                     }
 
-                    // Move
+                    // Set the start position for the next tab
                     x += width;
                 }
 
                 // Draw selected tab strip
-                Render2D.FillRectangle(new Rectangle(0, DockPanel.DefaultHeaderHeight - 2, Width, 2), containsFocus ? style.BackgroundSelected : style.BackgroundNormal);
+                Render2D.FillRectangle(new Rectangle(0, HeaderRectangle.Height - 2, Width, 2), containsFocus ? style.BackgroundSelected : style.BackgroundNormal);
             }
         }
 
@@ -355,6 +396,7 @@ namespace FlaxEditor.GUI.Docking
             if (IsSingleFloatingWindow)
                 return base.OnMouseDown(location, button);
             MouseDownWindow = GetTabAtPos(location, out IsMouseDownOverCross);
+            MouseStartPosition = location;
 
             // Check buttons
             if (button == MouseButton.Left)
@@ -441,6 +483,20 @@ namespace FlaxEditor.GUI.Docking
                         StartDrag(MouseDownWindow);
                     MouseDownWindow = null;
                 }
+                // Check if single tab is tried to be moved
+                else if (MouseDownWindow != null && _panel.TabsCount <= 1)
+                {
+                    if ((MousePosition - MouseStartPosition).Length > 3)
+                    {
+                        // Clear flag
+                        IsMouseLeftButtonDown = false;
+
+                        // Check tab under the mouse
+                        if (!IsMouseDownOverCross && MouseDownWindow != null)
+                            StartDrag(MouseDownWindow);
+                        MouseDownWindow = null;
+                    }
+                }
                 // Check if has more than one tab to change order
                 else if (MouseDownWindow != null && _panel.TabsCount > 1)
                 {
@@ -522,7 +578,7 @@ namespace FlaxEditor.GUI.Docking
             if (IsSingleFloatingWindow)
                 rect = new Rectangle(0, 0, Width, Height);
             else
-                rect = new Rectangle(0, DockPanel.DefaultHeaderHeight, Width, Height - DockPanel.DefaultHeaderHeight);
+                rect = new Rectangle(0, HeaderRectangle.Height, Width, Height - HeaderRectangle.Height);
         }
 
         private DragDropEffect TrySelectTabUnderLocation(ref Float2 location)

Source/Editor/GUI/Docking/DockWindow.cs

@@ -182,6 +182,25 @@ namespace FlaxEditor.GUI.Docking
         /// <param name="size">Window size, set <see cref="Float2.Zero"/> to use default.</param>
         /// <param name="position">Window location.</param>
         public void ShowFloating(Float2 location, Float2 size, WindowStartPosition position = WindowStartPosition.CenterParent)
+        {
+            CreateFloating(location, size, position, true);
+        }
+
+        /// <summary>
+        /// Creates the window in a floating state.
+        /// </summary>
+        public void CreateFloating()
+        {
+            CreateFloating(Float2.Zero, Float2.Zero);
+        }
+        /// <summary>
+        /// Creates the window in a floating state.
+        /// </summary>
+        /// <param name="location">Window location.</param>
+        /// <param name="size">Window size, set <see cref="Float2.Zero"/> to use default.</param>
+        /// <param name="position">Window location.</param>
+        /// <param name="showWindow">Window visibility.</param>
+        public void CreateFloating(Float2 location, Float2 size, WindowStartPosition position = WindowStartPosition.CenterParent, bool showWindow = false)
         {
             Undock();
 
@@ -199,14 +218,17 @@ namespace FlaxEditor.GUI.Docking
             windowGUI.UnlockChildrenRecursive();
             windowGUI.PerformLayout();
 
-            // Show
-            window.Show();
-            window.BringToFront();
-            window.Focus();
-            OnShow();
+            if (showWindow)
+            {
+                // Show
+                window.Show();
+                window.BringToFront();
+                window.Focus();
+                OnShow();
 
-            // Perform layout again
-            windowGUI.PerformLayout();
+                // Perform layout again
+                windowGUI.PerformLayout();
+            }
         }
 
         /// <summary>

Source/Editor/GUI/Docking/FloatWindowDockPanel.cs

@@ -11,6 +11,42 @@ namespace FlaxEditor.GUI.Docking
     /// <seealso cref="DockPanel" />
     public class FloatWindowDockPanel : DockPanel
     {
+        private class FloatWindowDecorations : WindowDecorations
+        {
+            private FloatWindowDockPanel _panel;
+            
+            public FloatWindowDecorations(FloatWindowDockPanel panel)
+            : base(panel.RootWindow)
+            {
+                _panel = panel;
+            }
+            
+            /// <inheritdoc />
+            public override bool OnMouseDown(Float2 location, MouseButton button)
+            {
+                if (Title.Bounds.Contains(location) && button == MouseButton.Left)
+                {
+                    _panel.BeginDrag();
+                    return true;
+                }
+                return base.OnMouseDown(location, button);
+            }
+
+#if !PLATFORM_WINDOWS
+            /// <inheritdoc />
+            protected override WindowHitCodes OnHitTest(ref Float2 mouse)
+            {
+                var hit = base.OnHitTest(ref mouse);
+                if (hit == WindowHitCodes.Caption)
+                {
+                    // Override the system behaviour when interacting with the caption area
+                    hit = WindowHitCodes.Client;
+                }
+                return hit;
+            }
+#endif
+        }
+
         private MasterDockPanel _masterPanel;
         private WindowRootControl _window;
 
@@ -40,6 +76,26 @@ namespace FlaxEditor.GUI.Docking
             Parent = window;
             _window.Window.Closing += OnClosing;
             _window.Window.LeftButtonHit += OnLeftButtonHit;
+            
+            if (Utilities.Utils.UseCustomWindowDecorations())
+            {
+                var decorations = Parent.AddChild(new FloatWindowDecorations(this));
+                decorations.SetAnchorPreset(AnchorPresets.HorizontalStretchTop, false);
+            }
+        }
+        
+        /// <inheritdoc />
+        protected override void PerformLayoutBeforeChildren()
+        {
+            base.PerformLayoutBeforeChildren();
+            
+            var decorations = Parent.GetChild<FloatWindowDecorations>();
+            if (decorations != null)
+            {
+                // Apply offset for the title bar
+                foreach (var child in Children)
+                    child.Bounds = child.Bounds with { Y = decorations.Height, Height = Parent.Height - decorations.Height };
+            }
         }
 
         /// <summary>
@@ -52,7 +108,7 @@ namespace FlaxEditor.GUI.Docking
                 return;
 
             // Create docking hint window
-            DockHintWindow.Create(this);
+            WindowDragHelper.StartDragging(this);
         }
 
         /// <summary>
@@ -71,22 +127,28 @@ namespace FlaxEditor.GUI.Docking
             settings.Title = title;
             settings.Size = size;
             settings.Position = location;
-            settings.MinimumSize = new Float2(1);
+            settings.MinimumSize = new Float2(200, 150);
             settings.MaximumSize = Float2.Zero; // Unlimited size
             settings.Fullscreen = false;
             settings.HasBorder = true;
-            settings.SupportsTransparency = false;
+            settings.SupportsTransparency = true;
             settings.ActivateWhenFirstShown = true;
             settings.AllowInput = true;
             settings.AllowMinimize = true;
             settings.AllowMaximize = true;
             settings.AllowDragAndDrop = true;
             settings.IsTopmost = false;
-            settings.IsRegularWindow = true;
+            settings.Type = WindowType.Regular;
             settings.HasSizingFrame = true;
             settings.ShowAfterFirstPaint = false;
             settings.ShowInTaskbar = true;
             settings.StartPosition = startPosition;
+            
+            if (Utilities.Utils.UseCustomWindowDecorations())
+            {
+                settings.HasBorder = false;
+                //settings.HasSizingFrame = false;
+            }
 
             // Create window
             return Platform.CreateWindow(ref settings);

Source/Editor/GUI/Docking/MasterDockPanel.cs

@@ -81,7 +81,6 @@ namespace FlaxEditor.GUI.Docking
         public DockPanel HitTest(ref Float2 position, FloatWindowDockPanel excluded)
         {
             // Check all floating windows
-            // TODO: gather windows order and take it into account when performing test
             for (int i = 0; i < FloatingPanels.Count; i++)
             {
                 var win = FloatingPanels[i];
@@ -94,9 +93,44 @@ namespace FlaxEditor.GUI.Docking
             }
 
             // Base
+            //if (!Root?.RootWindow.Window.IsFocused ?? false)
+            //    return null;
             return base.HitTest(ref position);
         }
 
+        /// <summary>
+        /// Performs hit test over dock panel.
+        /// </summary>
+        /// <param name="position">Window space position to test.</param>
+        /// <param name="excluded">Floating window to omit during searching (and all docked to that one).</param>
+        /// <param name="hitResults">Results of the hit test</param>
+        /// <returns>True if any dock panels were hit, otherwise false.</returns>
+        public bool HitTest(ref Float2 position, FloatWindowDockPanel excluded, out DockPanel[] hitResults)
+        {
+            // Check all floating windows
+            List<DockPanel> results = new(FloatingPanels.Count);
+            for (int i = 0; i < FloatingPanels.Count; i++)
+            {
+                var win = FloatingPanels[i];
+                if (win.Visible && win != excluded)
+                {
+                    var result = win.HitTest(ref position);
+                    if (result != null)
+                        results.Add(result);
+                }
+            }
+
+            // Base
+            //if (!Root?.RootWindow.Window.IsFocused ?? false)
+            //    return null;
+            var baseResult = base.HitTest(ref position);
+            if (baseResult != null)
+                results.Add(baseResult);
+
+            hitResults = results.ToArray();
+            return hitResults.Length > 0;
+        }
+
         internal void LinkWindow(DockWindow window)
         {
             // Add to the windows list

Source/Editor/GUI/Docking/WindowDragHelper.cs

@@ -0,0 +1,458 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+using System;
+using FlaxEngine;
+using FlaxEngine.GUI;
+
+namespace FlaxEditor.GUI.Docking
+{
+    /// <summary>
+    /// Helper class used to handle docking windows dragging and docking.
+    /// </summary>
+    public class WindowDragHelper
+    {
+        private FloatWindowDockPanel _toMove;
+
+        private Float2 _dragOffset;
+        private Rectangle _rectDock;
+        private Float2 _mouse;
+        private DockState _toSet;
+        private DockPanel _toDock;
+        private Window _dragSourceWindow;
+
+        private Rectangle _rLeft, _rRight, _rBottom, _rUpper, _rCenter;
+        private Control _dockHintDown, _dockHintUp, _dockHintLeft, _dockHintRight, _dockHintCenter;
+
+        /// <summary>
+        /// The hint control size.
+        /// </summary>
+        public const float HintControlSize = 32.0f;
+
+        /// <summary>
+        /// The opacity of the dragged window when hint controls are shown.
+        /// </summary>
+        public const float DragWindowOpacity = 0.4f;
+        
+        /// <summary>
+        /// Returns true if any windows are being dragged.
+        /// </summary>
+        public static bool IsDragActive { get; private set; }
+
+        private WindowDragHelper(FloatWindowDockPanel toMove, Window dragSourceWindow)
+        {
+            IsDragActive = true;
+            _toMove = toMove;
+            _toSet = DockState.Float;
+            var window = toMove.Window.Window;
+
+            // Bind events
+            FlaxEngine.Scripting.Update += OnUpdate;
+            window.MouseUp += OnMouseUp;
+            
+            // Update rectangles
+            UpdateRects(Platform.MousePosition);
+            
+            // Ensure the dragged window stays on top of every other window
+            window.IsAlwaysOnTop = true;
+
+            _dragSourceWindow = dragSourceWindow;
+            if (_dragSourceWindow != null) // Detaching a tab from existing window
+            {
+                _dragOffset = new Float2(window.Size.X / 2, 10.0f);
+                
+                _dragSourceWindow.MouseUp += OnMouseUp; // The mouse up event is sent to the source window on Windows
+
+                // TODO: when detaching tab in floating window (not main window), the drag source window is still main window?
+                var dragSourceWindowWayland = toMove.MasterPanel?.RootWindow.Window ?? Editor.Instance.Windows.MainWindow;
+                window.DoDragDrop(window.Title, _dragOffset, dragSourceWindowWayland);
+            }
+            else
+            {
+                _dragOffset = window.MousePosition;
+                window.DoDragDrop(window.Title, _dragOffset, window);
+            }
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources.
+        /// </summary>
+        public void Dispose()
+        {
+            IsDragActive = false;
+            var window = _toMove?.Window?.Window;
+
+            // Unbind events
+            FlaxEngine.Scripting.Update -= OnUpdate;
+            if (window != null)
+                window.MouseUp -= OnMouseUp;
+            if (_dragSourceWindow != null)
+                _dragSourceWindow.MouseUp -= OnMouseUp;
+
+            RemoveDockHints();
+
+            if (_toMove == null)
+                return;
+
+            if (window != null)
+            {
+                window.Opacity = 1.0f;
+                window.IsAlwaysOnTop = false;
+                window.BringToFront();
+            }
+
+            // Check if window won't be docked
+            if (_toSet == DockState.Float)
+            {
+                if (window == null)
+                    return;
+
+                // Show base window
+                window.Show();
+            }
+            else
+            {
+                bool hasNoChildPanels = _toMove.ChildPanelsCount == 0;
+
+                // Check if window has only single tab
+                if (hasNoChildPanels && _toMove.TabsCount == 1)
+                {
+                    // Dock window
+                    _toMove.GetTab(0).Show(_toSet, _toDock);
+                }
+                // Check if dock as tab and has no child panels
+                else if (hasNoChildPanels && _toSet == DockState.DockFill)
+                {
+                    // Dock all tabs
+                    while (_toMove.TabsCount > 0)
+                    {
+                        _toMove.GetTab(0).Show(DockState.DockFill, _toDock);
+                    }
+                }
+                else
+                {
+                    var selectedTab = _toMove.SelectedTab;
+
+                    // Dock the first tab into the target location
+                    if (_toMove.TabsCount > 0)
+                    {
+                        var firstTab = _toMove.GetTab(0);
+                        firstTab.Show(_toSet, _toDock);
+
+                        // Dock rest of the tabs
+                        while (_toMove.TabsCount > 0)
+                        {
+                            _toMove.GetTab(0).Show(DockState.DockFill, firstTab);
+                        }
+                    }
+
+                    // Keep selected tab being selected
+                    selectedTab?.SelectTab();
+                }
+
+                // Focus target window
+                _toDock.Root.Focus();
+            }
+
+            _toMove = null;
+        }
+
+        /// <summary>
+        /// Start dragging a floating dock panel.
+        /// </summary>
+        /// <param name="toMove">Floating dock panel to move.</param>
+        /// <returns>The window drag helper object.</returns>
+        public static WindowDragHelper StartDragging(FloatWindowDockPanel toMove)
+        {
+            if (toMove == null)
+                throw new ArgumentNullException();
+
+            return new WindowDragHelper(toMove, null);
+        }
+
+        /// <summary>
+        /// Start dragging a docked panel into a floating window.
+        /// </summary>
+        /// <param name="toMove">Dock window to move.</param>
+        /// <param name="dragSourceWindow">The window where dragging started from.</param>
+        /// <returns>The window drag helper object.</returns>
+        public static WindowDragHelper StartDragging(DockWindow toMove, Window dragSourceWindow)
+        {
+            if (toMove == null)
+                throw new ArgumentNullException();
+
+            // Create floating window
+            toMove.CreateFloating();
+
+            // Get floating panel
+            var window = (WindowRootControl)toMove.Root;
+            var floatingPanelToMove = window.GetChild(0) as FloatWindowDockPanel;
+
+            return new WindowDragHelper(floatingPanelToMove, dragSourceWindow);
+        }
+
+        private sealed class DragVisuals : Control
+        {
+            public DragVisuals()
+            {
+                AnchorPreset = AnchorPresets.StretchAll;
+                Offsets = Margin.Zero;
+            }
+
+            public override void Draw()
+            {
+                base.Draw();
+                Render2D.DrawRectangle(new Rectangle(Float2.Zero, Size), Style.Current.SelectionBorder);
+            }
+        }
+
+        private void AddDockHints()
+        {
+            if (_toDock == null)
+                return;
+
+            if (_toDock.RootWindow.Window != _dragSourceWindow)
+                _toDock.RootWindow.Window.MouseUp += OnMouseUp;
+
+            _dockHintDown = AddHintControl(new Float2(0.5f, 1));
+            _dockHintUp = AddHintControl(new Float2(0.5f, 0));
+            _dockHintLeft = AddHintControl(new Float2(0, 0.5f));
+            _dockHintRight = AddHintControl(new Float2(1, 0.5f));
+            _dockHintCenter = AddHintControl(new Float2(0.5f, 0.5f));
+
+            Control AddHintControl(Float2 pivot)
+            {
+                DragVisuals hintControl = _toDock.AddChild<DragVisuals>();
+                hintControl.Size = new Float2(HintControlSize);
+                hintControl.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                hintControl.Pivot = pivot;
+                hintControl.PivotRelative = true;
+                return hintControl;
+            }
+        }
+        
+        private void RemoveDockHints()
+        {
+            if (_toDock == null)
+                return;
+
+            if (_toDock.RootWindow.Window != _dragSourceWindow)
+                _toDock.RootWindow.Window.MouseUp -= OnMouseUp;
+
+            _dockHintDown?.Parent.RemoveChild(_dockHintDown);
+            _dockHintUp?.Parent.RemoveChild(_dockHintUp);
+            _dockHintLeft?.Parent.RemoveChild(_dockHintLeft);
+            _dockHintRight?.Parent.RemoveChild(_dockHintRight);
+            _dockHintCenter?.Parent.RemoveChild(_dockHintCenter);
+            _dockHintDown = _dockHintUp = _dockHintLeft = _dockHintRight = _dockHintCenter = null;
+        }
+
+        private void UpdateRects(Float2 mousePos)
+        {
+            // Cache mouse position
+            _mouse = mousePos;
+
+            // Check intersection with any dock panel
+            DockPanel dockPanel = null;
+            if (_toMove.MasterPanel.HitTest(ref _mouse, _toMove, out var hitResults))
+            {
+                dockPanel = hitResults[0];
+
+                // Prefer panel which currently has focus
+                foreach (var hit in hitResults)
+                {
+                    if (hit.RootWindow.Window.IsFocused)
+                    {
+                        dockPanel = hit;
+                        break;
+                    }
+                }
+
+                // Prefer panel in the same window we hit earlier
+                if (dockPanel?.RootWindow != _toDock?.RootWindow)
+                {
+                    foreach (var hit in hitResults)
+                    {
+                        if (hit.RootWindow == _toDock?.RootWindow)
+                        {
+                            dockPanel = _toDock;
+                            break;
+                        }
+                    }
+                }
+            }
+            
+            if (dockPanel != _toDock)
+            {
+                RemoveDockHints();
+                _toDock = dockPanel;
+                AddDockHints();
+
+                // Make sure the all the dock hint areas are not under other windows
+                _toDock?.RootWindow.Window.BringToFront();
+                //_toDock?.RootWindow.Window.Focus();
+
+                // Make the dragged window transparent when dock hints are visible
+                _toMove.Window.Window.Opacity = _toDock == null ? 1.0f : DragWindowOpacity;
+            }
+            
+            // Check dock state to use
+            bool showProxyHints = _toDock != null;
+            bool showBorderHints = showProxyHints;
+            bool showCenterHint = showProxyHints;
+            Control hoveredHintControl = null;
+            Float2 hoveredSizeOverride = Float2.Zero;
+            if (showProxyHints)
+            {
+                // If moved window has not only tabs but also child panels disable docking as tab
+                if (_toMove.ChildPanelsCount > 0)
+                    showCenterHint = false;
+
+                // Disable docking windows with one or more dock panels inside
+                if (_toMove.ChildPanelsCount > 0)
+                    showBorderHints = false;
+
+                // Get dock area
+                _rectDock = _toDock.DockAreaBounds;
+
+                // Cache dock rectangles
+                var size = _rectDock.Size / Platform.DpiScale;
+                var offset = _toDock.PointFromScreen(_rectDock.Location);
+                var borderMargin = 4.0f;
+                var hintWindowsSize = HintControlSize;
+                var hintWindowsSize2 = hintWindowsSize * 0.5f;
+                var hintPreviewSize = new Float2(Math.Max(HintControlSize * 2, size.X * 0.5f), Math.Max(HintControlSize * 2, size.Y * 0.5f));
+                var centerX = size.X * 0.5f;
+                var centerY = size.Y * 0.5f;
+                _rUpper = new Rectangle(centerX - hintWindowsSize2, borderMargin, hintWindowsSize, hintWindowsSize) + offset;
+                _rBottom = new Rectangle(centerX - hintWindowsSize2, size.Y - hintWindowsSize - borderMargin, hintWindowsSize, hintWindowsSize) + offset;
+                _rLeft = new Rectangle(borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
+                _rRight = new Rectangle(size.X - hintWindowsSize - borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
+                _rCenter = new Rectangle(centerX - hintWindowsSize2, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
+
+                // Hit test, and calculate the approximation for filled area when hovered over the hint
+                DockState toSet = DockState.Float;
+                if (showBorderHints)
+                {
+                    if (_rUpper.Contains(_toDock.PointFromScreen(_mouse)))
+                    {
+                        toSet = DockState.DockTop;
+                        hoveredHintControl = _dockHintUp;
+                        hoveredSizeOverride = new Float2(size.X, hintPreviewSize.Y);
+                    }
+                    else if (_rBottom.Contains(_toDock.PointFromScreen(_mouse)))
+                    {
+                        toSet = DockState.DockBottom;
+                        hoveredHintControl = _dockHintDown;
+                        hoveredSizeOverride = new Float2(size.X, hintPreviewSize.Y);
+                    }
+                    else if (_rLeft.Contains(_toDock.PointFromScreen(_mouse)))
+                    {
+                        toSet = DockState.DockLeft;
+                        hoveredHintControl = _dockHintLeft;
+                        hoveredSizeOverride = new Float2(hintPreviewSize.X, size.Y);
+                    }
+                    else if (_rRight.Contains(_toDock.PointFromScreen(_mouse)))
+                    {
+                        toSet = DockState.DockRight;
+                        hoveredHintControl = _dockHintRight;
+                        hoveredSizeOverride = new Float2(hintPreviewSize.X, size.Y);
+                    }
+                }
+                if (showCenterHint && _rCenter.Contains(_toDock.PointFromScreen(_mouse)))
+                {
+                    toSet = DockState.DockFill;
+                    hoveredHintControl = _dockHintCenter;
+                    hoveredSizeOverride = new Float2(size.X, size.Y);
+                }
+
+                _toSet = toSet;
+            }
+            else
+            {
+                _toSet = DockState.Float;
+            }
+            
+            // Update sizes and opacity of hint controls
+            if (_toDock != null)
+            {
+                if (hoveredHintControl != _dockHintDown)
+                {
+                    _dockHintDown.Size = new Float2(HintControlSize);
+                    _dockHintDown.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+                if (hoveredHintControl != _dockHintLeft)
+                {
+                    _dockHintLeft.Size = new Float2(HintControlSize);
+                    _dockHintLeft.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+                if (hoveredHintControl != _dockHintRight)
+                {
+                    _dockHintRight.Size = new Float2(HintControlSize);
+                    _dockHintRight.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+                if (hoveredHintControl != _dockHintUp)
+                {
+                    _dockHintUp.Size = new Float2(HintControlSize);
+                    _dockHintUp.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+                if (hoveredHintControl != _dockHintCenter)
+                {
+                    _dockHintCenter.Size = new Float2(HintControlSize);
+                    _dockHintCenter.BackgroundColor = Style.Current.Selection.AlphaMultiplied(0.6f);
+                }
+
+                if (_toSet != DockState.Float)
+                {
+                    if (hoveredHintControl != null)
+                    {
+                        hoveredHintControl.BackgroundColor = Style.Current.Selection.AlphaMultiplied(1.0f);
+                        hoveredHintControl.Size = hoveredSizeOverride;
+                    }
+                }
+            }
+
+            // Update hint controls visibility and location
+            if (showProxyHints)
+            {
+                if (hoveredHintControl != _dockHintDown)
+                    _dockHintDown.Location = _rBottom.Location;
+                if (hoveredHintControl != _dockHintLeft)
+                    _dockHintLeft.Location = _rLeft.Location;
+                if (hoveredHintControl != _dockHintRight)
+                    _dockHintRight.Location = _rRight.Location;
+                if (hoveredHintControl != _dockHintUp)
+                    _dockHintUp.Location = _rUpper.Location;
+                if (hoveredHintControl != _dockHintCenter)
+                    _dockHintCenter.Location = _rCenter.Location;
+                
+                _dockHintDown.Visible = showProxyHints & showBorderHints;
+                _dockHintLeft.Visible = showProxyHints & showBorderHints;
+                _dockHintRight.Visible = showProxyHints & showBorderHints;
+                _dockHintUp.Visible = showProxyHints & showBorderHints;
+                _dockHintCenter.Visible = showProxyHints & showCenterHint;
+            }
+        }
+
+        private void OnMouseUp(ref Float2 location, MouseButton button, ref bool handled)
+        {
+            if (button == MouseButton.Left)
+                Dispose();
+        }
+
+        private void OnUpdate()
+        {
+            var mousePos = Platform.MousePosition;
+
+            if (_mouse != mousePos)
+                OnMouseMove(mousePos);
+        }
+        
+        private void OnMouseMove(Float2 mousePos)
+        {
+            if (_dragSourceWindow != null)
+                _toMove.Window.Window.Position = mousePos - _dragOffset;
+
+            UpdateRects(mousePos);
+        }
+    }
+}

Source/Editor/GUI/Input/ValueBox.cs

@@ -266,6 +266,7 @@ namespace FlaxEditor.GUI.Input
             return base.OnMouseDown(location, button);
         }
 
+#if !PLATFORM_SDL
         /// <inheritdoc />
         public override void OnMouseMove(Float2 location)
         {
@@ -292,13 +293,45 @@ namespace FlaxEditor.GUI.Input
             base.OnMouseMove(location);
         }
 
+#else
+
+        /// <inheritdoc />
+        public override void OnMouseMoveRelative(Float2 mouseMotion)
+        {
+            var location = Root.TrackingMouseOffset;
+            if (_isSliding)
+            {
+                // Update sliding
+                ApplySliding(Root.TrackingMouseOffset.X * _slideSpeed);
+                return;
+            }
+
+            // Update cursor type so user knows they can slide value
+            if (CanUseSliding && SlideRect.Contains(location) && !_isSliding)
+            {
+                Cursor = CursorType.SizeWE;
+                _cursorChanged = true;
+            }
+            else if (_cursorChanged && !_isSliding)
+            {
+                Cursor = CursorType.Default;
+                _cursorChanged = false;
+            }
+
+            base.OnMouseMoveRelative(mouseMotion);
+        }
+
+#endif
+
         /// <inheritdoc />
         public override bool OnMouseUp(Float2 location, MouseButton button)
         {
             if (button == MouseButton.Left && _isSliding)
             {
+#if !PLATFORM_SDL
                 // End sliding and return mouse to original location
                 RootWindow.MousePosition = _mouseClickedPosition;
+#endif
                 EndSliding();
                 return true;
             }

Source/Editor/GUI/ItemsListContextMenu.cs

@@ -51,6 +51,11 @@ namespace FlaxEditor.GUI
             /// </summary>
             public float SortScore;
 
+            /// <summary>
+            /// Wether the query highlights should be draw.
+            /// </summary>
+            public bool DrawHighlights = true;
+
             /// <summary>
             /// Occurs when items gets clicked by the user.
             /// </summary>
@@ -165,7 +170,7 @@ namespace FlaxEditor.GUI
                     Render2D.FillRectangle(new Rectangle(Float2.Zero, Size), style.BackgroundHighlighted);
 
                 // Draw all highlights
-                if (_highlights != null)
+                if (DrawHighlights && _highlights != null)
                 {
                     var color = style.ProgressNormal * 0.6f;
                     for (int i = 0; i < _highlights.Count; i++)
@@ -514,20 +519,15 @@ namespace FlaxEditor.GUI
             var items = ItemsPanel.Children;
             for (int i = 0; i < items.Count; i++)
             {
-                if (items[i] is Item item && item.Visible)
+                var currentItem = items[i];
+                if (currentItem is Item item && item.Visible)
                     result.Add(item);
-            }
-            if (_categoryPanels != null)
-            {
-                for (int i = 0; i < _categoryPanels.Count; i++)
+                else if (currentItem is DropPanel category && (!ignoreFoldedCategories || !category.IsClosed) && currentItem.Visible)
                 {
-                    var category = _categoryPanels[i];
-                    if (!category.Visible || (ignoreFoldedCategories && category is DropPanel panel && panel.IsClosed))
-                        continue;
                     for (int j = 0; j < category.Children.Count; j++)
                     {
-                        if (category.Children[j] is Item item2 && item2.Visible)
-                            result.Add(item2);
+                        if (category.Children[j] is Item categoryItem && categoryItem.Visible)
+                            result.Add(categoryItem);
                     }
                 }
             }
@@ -591,10 +591,6 @@ namespace FlaxEditor.GUI
                 var items = GetVisibleItems(!controlDown);
                 var focusedIndex = items.IndexOf(focusedItem);
 
-                // If the user hasn't selected anything yet and is holding control, focus first folded item
-                if (focusedIndex == -1 && controlDown)
-                    focusedIndex = GetVisibleItems(true).Count - 1;
-
                 int delta = key == KeyboardKeys.ArrowDown ? -1 : 1;
                 int nextIndex = Mathf.Wrap(focusedIndex - delta, 0, items.Count - 1);
                 var nextItem = items[nextIndex];

Source/Editor/GUI/MainMenu.cs

@@ -12,16 +12,6 @@ namespace FlaxEditor.GUI
     /// <seealso cref="FlaxEngine.GUI.ContainerControl" />
     public sealed class MainMenu : ContainerControl
     {
-#if PLATFORM_WINDOWS
-        private bool _useCustomWindowSystem;
-        private Image _icon;
-        private Label _title;
-        private Button _closeButton;
-        private Button _minimizeButton;
-        private Button _maximizeButton;
-        private LocalizedString _charChromeRestore, _charChromeMaximize;
-        private Window _window;
-#endif
         private MainMenuButton _selected;
 
         /// <summary>
@@ -60,200 +50,12 @@ namespace FlaxEditor.GUI
         /// <summary>
         /// Initializes a new instance of the <see cref="MainMenu"/> class.
         /// </summary>
-        /// <param name="mainWindow">The main window.</param>
-        public MainMenu(RootControl mainWindow)
+        public MainMenu()
         : base(0, 0, 0, 20)
         {
             AutoFocus = false;
             AnchorPreset = AnchorPresets.HorizontalStretchTop;
-
-#if PLATFORM_WINDOWS
-            _useCustomWindowSystem = !Editor.Instance.Options.Options.Interface.UseNativeWindowSystem;
-            if (_useCustomWindowSystem)
-            {
-                BackgroundColor = Style.Current.LightBackground;
-                Height = 28;
-
-                var windowIcon = FlaxEngine.Content.LoadAsyncInternal<Texture>(EditorAssets.WindowIcon);
-                FontAsset windowIconsFont = FlaxEngine.Content.LoadAsyncInternal<FontAsset>(EditorAssets.WindowIconsFont);
-                Font iconFont = windowIconsFont?.CreateFont(9);
-
-                _window = mainWindow.RootWindow.Window;
-                _window.HitTest += OnHitTest;
-                _window.Closed += OnWindowClosed;
-
-                ScriptsBuilder.GetBinariesConfiguration(out _, out _, out _, out var configuration);
-
-                _icon = new Image
-                {
-                    Margin = new Margin(6, 6, 6, 6),
-                    Brush = new TextureBrush(windowIcon),
-                    Color = Style.Current.Foreground,
-                    KeepAspectRatio = false,
-                    TooltipText = string.Format("{0}\nVersion {1}\nConfiguration {3}\nGraphics {2}", _window.Title, Globals.EngineVersion, GPUDevice.Instance.RendererType, configuration),
-                    Parent = this,
-                };
-
-                _title = new Label(0, 0, Width, Height)
-                {
-                    Text = _window.Title,
-                    HorizontalAlignment = TextAlignment.Center,
-                    VerticalAlignment = TextAlignment.Center,
-                    ClipText = true,
-                    TextColor = Style.Current.ForegroundGrey,
-                    TextColorHighlighted = Style.Current.ForegroundGrey,
-                    Parent = this,
-                };
-
-                _closeButton = new Button
-                {
-                    Text = ((char)EditorAssets.SegMDL2Icons.ChromeClose).ToString(),
-                    Font = new FontReference(iconFont),
-                    BackgroundColor = Color.Transparent,
-                    BorderColor = Color.Transparent,
-                    BorderColorHighlighted = Color.Transparent,
-                    BorderColorSelected = Color.Transparent,
-                    TextColor = Style.Current.Foreground,
-                    Width = 46,
-                    BackgroundColorHighlighted = Color.Red,
-                    BackgroundColorSelected = Color.Red.RGBMultiplied(1.3f),
-                    Parent = this,
-                };
-                _closeButton.Clicked += () => _window.Close(ClosingReason.User);
-
-                _minimizeButton = new Button
-                {
-                    Text = ((char)EditorAssets.SegMDL2Icons.ChromeMinimize).ToString(),
-                    Font = new FontReference(iconFont),
-                    BackgroundColor = Color.Transparent,
-                    BorderColor = Color.Transparent,
-                    BorderColorHighlighted = Color.Transparent,
-                    BorderColorSelected = Color.Transparent,
-                    TextColor = Style.Current.Foreground,
-                    Width = 46,
-                    BackgroundColorHighlighted = Style.Current.LightBackground.RGBMultiplied(1.3f),
-                    Parent = this,
-                };
-                _minimizeButton.Clicked += () => _window.Minimize();
-
-                _maximizeButton = new Button
-                {
-                    Text = ((char)(_window.IsMaximized ? EditorAssets.SegMDL2Icons.ChromeRestore : EditorAssets.SegMDL2Icons.ChromeMaximize)).ToString(),
-                    Font = new FontReference(iconFont),
-                    BackgroundColor = Color.Transparent,
-                    BorderColor = Color.Transparent,
-                    BorderColorHighlighted = Color.Transparent,
-                    BorderColorSelected = Color.Transparent,
-                    TextColor = Style.Current.Foreground,
-                    Width = 46,
-                    BackgroundColorHighlighted = Style.Current.LightBackground.RGBMultiplied(1.3f),
-                    Parent = this,
-                };
-                _maximizeButton.Clicked += () =>
-                {
-                    if (_window.IsMaximized)
-                        _window.Restore();
-                    else
-                        _window.Maximize();
-                };
-                _charChromeRestore = ((char)EditorAssets.SegMDL2Icons.ChromeRestore).ToString();
-                _charChromeMaximize = ((char)EditorAssets.SegMDL2Icons.ChromeMaximize).ToString();
-            }
-            else
-#endif
-            {
-                BackgroundColor = Style.Current.LightBackground;
-            }
-        }
-
-#if PLATFORM_WINDOWS
-        /// <inheritdoc />
-        public override void Update(float deltaTime)
-        {
-            base.Update(deltaTime);
-
-            if (_maximizeButton != null)
-            {
-                _maximizeButton.Text = _window.IsMaximized ? _charChromeRestore : _charChromeMaximize;
-            }
-        }
-
-        private void OnWindowClosed()
-        {
-            if (_window != null)
-            {
-                _window.HitTest = null;
-                _window = null;
-            }
-        }
-
-        private WindowHitCodes OnHitTest(ref Float2 mouse)
-        {
-            var dpiScale = _window.DpiScale;
-
-            if (_window.IsMinimized)
-                return WindowHitCodes.NoWhere;
-
-            if (!_window.IsMaximized)
-            {
-                var pos = _window.ScreenToClient(mouse * dpiScale); // pos is not DPI adjusted
-                var winSize = _window.Size;
-
-                // Distance from which the mouse is considered to be on the border/corner
-                float distance = 5.0f * dpiScale;
-
-                if (pos.Y > winSize.Y - distance && pos.X < distance)
-                    return WindowHitCodes.BottomLeft;
-
-                if (pos.X > winSize.X - distance && pos.Y > winSize.Y - distance)
-                    return WindowHitCodes.BottomRight;
-
-                if (pos.Y < distance && pos.X < distance)
-                    return WindowHitCodes.TopLeft;
-
-                if (pos.Y < distance && pos.X > winSize.X - distance)
-                    return WindowHitCodes.TopRight;
-
-                if (pos.X > winSize.X - distance)
-                    return WindowHitCodes.Right;
-
-                if (pos.X < distance)
-                    return WindowHitCodes.Left;
-
-                if (pos.Y < distance)
-                    return WindowHitCodes.Top;
-
-                if (pos.Y > winSize.Y - distance)
-                    return WindowHitCodes.Bottom;
-            }
-
-            var mousePos = PointFromScreen(mouse * dpiScale);
-            var controlUnderMouse = GetChildAt(mousePos);
-            var isMouseOverSth = controlUnderMouse != null && controlUnderMouse != _title;
-            var rb = GetRightButton();
-            if (rb != null && _minimizeButton != null && new Rectangle(rb.UpperRight, _minimizeButton.BottomLeft - rb.UpperRight).Contains(ref mousePos) && !isMouseOverSth)
-                return WindowHitCodes.Caption;
-
-            return WindowHitCodes.Client;
-        }
-#endif
-
-        /// <summary>
-        /// Return the rightmost button.
-        /// </summary>
-        /// <returns>Rightmost button, null if there is no <see cref="MainMenuButton"/></returns>
-        private MainMenuButton GetRightButton()
-        {
-            MainMenuButton b = null;
-            foreach (var control in Children)
-            {
-                if (b == null && control is MainMenuButton)
-                    b = (MainMenuButton)control;
-
-                if (control is MainMenuButton && control.Right > b.Right)
-                    b = (MainMenuButton)control;
-            }
-            return b;
+            BackgroundColor = Style.Current.LightBackground;
         }
 
         /// <summary>
@@ -298,26 +100,6 @@ namespace FlaxEditor.GUI
             return result;
         }
 
-        /// <inheritdoc />
-        public override bool OnMouseDoubleClick(Float2 location, MouseButton button)
-        {
-            if (base.OnMouseDoubleClick(location, button))
-                return true;
-
-#if PLATFORM_WINDOWS
-            var child = GetChildAtRecursive(location);
-            if (_useCustomWindowSystem && child is not Button && child is not MainMenuButton)
-            {
-                if (_window.IsMaximized)
-                    _window.Restore();
-                else
-                    _window.Maximize();
-            }
-#endif
-
-            return true;
-        }
-
         /// <inheritdoc />
         public override bool OnKeyDown(KeyboardKeys key)
         {
@@ -333,16 +115,8 @@ namespace FlaxEditor.GUI
         protected override void PerformLayoutAfterChildren()
         {
             float x = 0;
-
-#if PLATFORM_WINDOWS
-            if (_useCustomWindowSystem)
-            {
-                // Icon
-                _icon.X = x;
-                _icon.Size = new Float2(Height);
-                x += _icon.Width;
-            }
-#endif
+            WindowDecorations decorations = Parent.GetChild<WindowDecorations>();
+            x += decorations?.Icon?.Width ?? 0;
 
             // Arrange controls
             MainMenuButton rightMostButton = null;
@@ -361,37 +135,21 @@ namespace FlaxEditor.GUI
                     x += b.Width;
                 }
             }
-
-#if PLATFORM_WINDOWS
-            if (_useCustomWindowSystem)
-            {
-                // Buttons
-                _closeButton.Height = Height;
-                _closeButton.X = Width - _closeButton.Width;
-                _maximizeButton.Height = Height;
-                _maximizeButton.X = _closeButton.X - _maximizeButton.Width;
-                _minimizeButton.Height = Height;
-                _minimizeButton.X = _maximizeButton.X - _minimizeButton.Width;
-
-                // Title
-                _title.Bounds = new Rectangle(x + 2, 0, _minimizeButton.Left - x - 4, Height);
-                //_title.Text = _title.Width < 300.0f ? Editor.Instance.ProjectInfo.Name : _window.Title;
-            }
-#endif
+            
+            // Fill the right side if title and buttons are not present
+            if (decorations?.Title == null)
+                Width = Parent.Width;
+            else
+                Width = x;
         }
 
-#if PLATFORM_WINDOWS
         /// <inheritdoc />
         public override void OnDestroy()
         {
             base.OnDestroy();
-
-            if (_window != null)
-            {
-                _window.Closed -= OnWindowClosed;
-                OnWindowClosed();
-            }
+            
+            if (_selected != null)
+                Selected = null;
         }
-#endif
     }
 }

Source/Editor/GUI/MainMenuButton.cs

@@ -42,14 +42,12 @@ namespace FlaxEditor.GUI
             Text = text;
 
             var style = Style.Current;
-#if PLATFORM_WINDOWS
-            if (Editor.Instance.Options.Options.Interface.UseNativeWindowSystem)
+            if (!Utilities.Utils.UseCustomWindowDecorations())
             {
                 BackgroundColorMouseOver = style.BackgroundHighlighted;
                 BackgroundColorMouseOverOpened = style.Background;
             }
             else
-#endif
             {
                 BackgroundColorMouseOver = BackgroundColorMouseOverOpened = style.LightBackground * 1.3f;
             }

Source/Editor/GUI/NavigationBar.cs

@@ -11,6 +11,9 @@ namespace FlaxEditor.GUI
     /// <seealso cref="FlaxEngine.GUI.Panel" />
     public class NavigationBar : Panel
     {
+        private float _toolstripHeight = 0;
+        private Margin _toolstripMargin;
+
         /// <summary>
         /// The default buttons margin.
         /// </summary>
@@ -50,9 +53,42 @@ namespace FlaxEditor.GUI
         {
             if (toolstrip == null)
                 return;
+
+            if (_toolstripHeight <= 0.0f)
+            {
+                // Cache initial toolstrip state
+                _toolstripHeight = toolstrip.Height;
+                _toolstripMargin = toolstrip.ItemsMargin;
+            }
+
+            // Control toolstrip bottom margin to prevent navigation bar scroll going over the buttons
+            var toolstripLocked = toolstrip.IsLayoutLocked;
+            toolstrip.IsLayoutLocked = true;
+            var toolstripHeight = _toolstripHeight;
+            var toolstripMargin = _toolstripMargin;
+            if (HScrollBar.Visible)
+            {
+                float scrollMargin = 8;
+                toolstripHeight += scrollMargin;
+                toolstripMargin.Bottom += scrollMargin;
+            }
+            toolstrip.Height = toolstripHeight;
+            toolstrip.IsLayoutLocked = toolstripLocked;
+            toolstrip.ItemsMargin = toolstripMargin;
+
             var lastToolstripButton = toolstrip.LastButton;
             var parentSize = Parent.Size;
             Bounds = new Rectangle(lastToolstripButton.Right + 8.0f, 0, parentSize.X - X - 8.0f, toolstrip.Height);
         }
+
+        /// <inheritdoc />
+        public override void PerformLayout(bool force = false)
+        {
+            base.PerformLayout(force);
+
+            // Stretch excluding toolstrip margin to fill the space
+            if (Parent is ToolStrip toolStrip)
+                Height = toolStrip.Height;
+        }
     }
 }

Source/Editor/GUI/Popups/RenamePopup.cs

@@ -130,6 +130,10 @@ namespace FlaxEditor.GUI
         /// <returns>Created popup.</returns>
         public static RenamePopup Show(Control control, Rectangle area, string value, bool isMultiline)
         {
+            // hardcoded flushing layout for tree controls
+            if (control is Tree.TreeNode treeNode && treeNode.ParentTree != null)
+                treeNode.ParentTree.FlushPendingPerformLayout();
+
             // Calculate the control size in the window space to handle scaled controls
             var upperLeft = control.PointToWindow(area.UpperLeft);
             var bottomRight = control.PointToWindow(area.BottomRight);

Source/Editor/GUI/Timeline/Tracks/EventTrack.cs

@@ -10,6 +10,7 @@ using System.Text;
 using FlaxEditor.GUI.Timeline.Undo;
 using FlaxEngine;
 using FlaxEngine.GUI;
+using FlaxEngine.Json;
 using FlaxEngine.Utilities;
 
 namespace FlaxEditor.GUI.Timeline.Tracks
@@ -54,7 +55,10 @@ namespace FlaxEditor.GUI.Timeline.Tracks
                 var paramTypeName = LoadName(stream);
                 e.EventParamsTypes[i] = TypeUtils.GetManagedType(paramTypeName);
                 if (e.EventParamsTypes[i] == null)
+                {
+                    Editor.LogError($"Unknown type {paramTypeName}.");
                     isInvalid = true;
+                }
             }
 
             if (isInvalid)
@@ -82,7 +86,7 @@ namespace FlaxEditor.GUI.Timeline.Tracks
                 for (int j = 0; j < paramsCount; j++)
                 {
                     stream.Read(dataBuffer, 0, e.EventParamsSizes[j]);
-                    key.Parameters[j] = Marshal.PtrToStructure(handle.AddrOfPinnedObject(), e.EventParamsTypes[j]);
+                    key.Parameters[j] = Utilities.Utils.ByteArrayToStructure(handle.AddrOfPinnedObject(), e.EventParamsTypes[j], e.EventParamsSizes[j]);
                 }
 
                 events[i] = new KeyframesEditor.Keyframe
@@ -125,8 +129,7 @@ namespace FlaxEditor.GUI.Timeline.Tracks
 
                 for (int j = 0; j < paramsCount; j++)
                 {
-                    Marshal.StructureToPtr(key.Parameters[j], ptr, true);
-                    Marshal.Copy(ptr, dataBuffer, 0, e.EventParamsSizes[j]);
+                    Utilities.Utils.StructureToByteArray(key.Parameters[j], e.EventParamsSizes[j], ptr, dataBuffer);
                     stream.Write(dataBuffer, 0, e.EventParamsSizes[j]);
                 }
             }
@@ -153,7 +156,7 @@ namespace FlaxEditor.GUI.Timeline.Tracks
         /// <summary>
         /// The event key data.
         /// </summary>
-        public struct EventKey
+        public struct EventKey : ICloneable
         {
             /// <summary>
             /// The parameters values.
@@ -178,6 +181,26 @@ namespace FlaxEditor.GUI.Timeline.Tracks
                 sb.Append(')');
                 return sb.ToString();
             }
+
+            /// <inheritdoc />
+            public object Clone()
+            {
+                if (Parameters == null)
+                    return new EventKey();
+
+                // Deep clone parameter values (especially boxed value types need to be duplicated to avoid referencing the same ones)
+                var parameters = new object[Parameters.Length];
+                for (int i = 0; i < parameters.Length; i++)
+                {
+                    var p = Parameters[i];
+                    if (p == null || p is FlaxEngine.Object)
+                        parameters[i] = Parameters[i];
+                    else
+                        parameters[i] = JsonSerializer.Deserialize(JsonSerializer.Serialize(p), p.GetType());
+                }
+
+                return new EventKey { Parameters = parameters };
+            }
         }
 
         /// <inheritdoc />
@@ -234,6 +257,7 @@ namespace FlaxEditor.GUI.Timeline.Tracks
                 var time = Timeline.CurrentTime;
                 if (!TryGetValue(out var value))
                     value = Events.Evaluate(time);
+                value = ((ICloneable)value).Clone();
 
                 // Find event at the current location
                 for (int i = Events.Keyframes.Count - 1; i >= 0; i--)

Source/Editor/GUI/Timeline/Tracks/KeyframesPropertyTrack.cs

@@ -77,7 +77,7 @@ namespace FlaxEditor.GUI.Timeline.Tracks
                 {
                     var time = stream.ReadSingle();
                     stream.Read(dataBuffer, 0, e.ValueSize);
-                    var value = Marshal.PtrToStructure(handle.AddrOfPinnedObject(), propertyType);
+                    var value = Utilities.Utils.ByteArrayToStructure(handle.AddrOfPinnedObject(), propertyType, e.ValueSize);
 
                     keyframes[i] = new KeyframesEditor.Keyframe
                     {
@@ -142,8 +142,7 @@ namespace FlaxEditor.GUI.Timeline.Tracks
                 for (int i = 0; i < keyframes.Count; i++)
                 {
                     var keyframe = keyframes[i];
-                    Marshal.StructureToPtr(keyframe.Value, ptr, true);
-                    Marshal.Copy(ptr, dataBuffer, 0, e.ValueSize);
+                    Utilities.Utils.StructureToByteArray(keyframe.Value, e.ValueSize, ptr, dataBuffer);
                     stream.Write(keyframe.Time);
                     stream.Write(dataBuffer);
                 }

Source/Editor/GUI/ToolStrip.cs

@@ -13,15 +13,7 @@ namespace FlaxEditor.GUI
     /// <seealso cref="FlaxEngine.GUI.ContainerControl" />
     public class ToolStrip : ContainerControl
     {
-        /// <summary>
-        /// The default margin vertically.
-        /// </summary>
-        public const int DefaultMarginV = 1;
-
-        /// <summary>
-        /// The default margin horizontally.
-        /// </summary>
-        public const int DefaultMarginH = 2;
+        private Margin _itemsMargin;
 
         /// <summary>
         /// Event fired when button gets clicked with the primary mouse button.
@@ -66,10 +58,26 @@ namespace FlaxEditor.GUI
             }
         }
 
+        /// <summary>
+        /// Gets or sets the space around items.
+        /// </summary>
+        public Margin ItemsMargin
+        {
+            get => _itemsMargin;
+            set
+            {
+                if (_itemsMargin != value)
+                {
+                    _itemsMargin = value;
+                    PerformLayout();
+                }
+            }
+        }
+
         /// <summary>
         /// Gets the height for the items.
         /// </summary>
-        public float ItemsHeight => Height - 2 * DefaultMarginV;
+        public float ItemsHeight => Height - _itemsMargin.Height;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="ToolStrip"/> class.
@@ -82,6 +90,7 @@ namespace FlaxEditor.GUI
             AnchorPreset = AnchorPresets.HorizontalStretchTop;
             BackgroundColor = Style.Current.LightBackground;
             Offsets = new Margin(0, 0, y, height * Editor.Instance.Options.Options.Interface.IconsScale);
+            _itemsMargin = new Margin(2, 2, 1, 1);
         }
 
         /// <summary>
@@ -161,7 +170,7 @@ namespace FlaxEditor.GUI
         protected override void PerformLayoutBeforeChildren()
         {
             // Arrange controls
-            float x = DefaultMarginH;
+            float x = _itemsMargin.Left;
             float h = ItemsHeight;
             for (int i = 0; i < _children.Count; i++)
             {
@@ -169,8 +178,8 @@ namespace FlaxEditor.GUI
                 if (c.Visible)
                 {
                     var w = c.Width;
-                    c.Bounds = new Rectangle(x, DefaultMarginV, w, h);
-                    x += w + DefaultMarginH;
+                    c.Bounds = new Rectangle(x, _itemsMargin.Top, w, h);
+                    x += w + _itemsMargin.Width;
                 }
             }
         }

Source/Editor/GUI/Tree/Tree.cs

@@ -41,6 +41,7 @@ namespace FlaxEditor.GUI.Tree
         private Margin _margin;
         private bool _autoSize = true;
         private bool _deferLayoutUpdate = false;
+        private TreeNode _lastSelectedNode;
 
         /// <summary>
         /// The TreeNode that is being dragged over. This could have a value when not dragging.
@@ -67,7 +68,7 @@ namespace FlaxEditor.GUI.Tree
         /// Gets the first selected node or null.
         /// </summary>
         public TreeNode SelectedNode => Selection.Count > 0 ? Selection[0] : null;
-        
+
         /// <summary>
         /// Allow nodes to Draw the root tree line.
         /// </summary>
@@ -364,6 +365,19 @@ namespace FlaxEditor.GUI.Tree
             BulkSelectUpdateExpanded(false);
         }
 
+        /// <summary>
+        /// Flushes any pending layout perming action that has been delayed until next update to optimize performance of the complex tree hierarchy.
+        /// </summary>
+        public void FlushPendingPerformLayout()
+        {
+            if (_deferLayoutUpdate)
+            {
+                base.PerformLayout();
+                AfterDeferredLayout?.Invoke();
+                _deferLayoutUpdate = false;
+            }
+        }
+
         /// <inheritdoc />
         public override void PerformLayout(bool force = false)
         {
@@ -378,25 +392,31 @@ namespace FlaxEditor.GUI.Tree
         public override void Update(float deltaTime)
         {
             if (_deferLayoutUpdate)
-            {
-                base.PerformLayout();
-                AfterDeferredLayout?.Invoke();
-                _deferLayoutUpdate = false;
-            }
+                FlushPendingPerformLayout();
+            var window = Root;
+            bool shiftDown = window.GetKey(KeyboardKeys.Shift);
+            bool keyUpArrow = window.GetKey(KeyboardKeys.ArrowUp);
+            bool keyDownArrow = window.GetKey(KeyboardKeys.ArrowDown);
 
-            var node = SelectedNode;
+            // Use last selection for last selected node if sift is down
+            if (Selection.Count < 2)
+                _lastSelectedNode = null;
+            else if (shiftDown)
+                _lastSelectedNode ??= Selection[^1];
+
+            // Skip root to prevent blocking input
+            if (_lastSelectedNode != null && _lastSelectedNode.IsRoot)
+                _lastSelectedNode = null;
+
+            var node = _lastSelectedNode ?? SelectedNode;
 
             // Check if has focus and if any node is focused and it isn't a root
             if (ContainsFocus && node != null && node.AutoFocus)
             {
-                var window = Root;
                 if (window.GetKeyDown(KeyboardKeys.ArrowUp) || window.GetKeyDown(KeyboardKeys.ArrowDown))
                     _keyUpdateTime = KeyUpdateTimeout;
                 if (_keyUpdateTime >= KeyUpdateTimeout && window is WindowRootControl windowRoot && windowRoot.Window.IsFocused)
                 {
-                    bool keyUpArrow = window.GetKey(KeyboardKeys.ArrowUp);
-                    bool keyDownArrow = window.GetKey(KeyboardKeys.ArrowDown);
-
                     // Check if arrow flags are different
                     if (keyDownArrow != keyUpArrow)
                     {
@@ -406,24 +426,38 @@ namespace FlaxEditor.GUI.Tree
                         Assert.AreNotEqual(-1, myIndex);
 
                         // Up
-                        TreeNode toSelect = null;
+                        List<TreeNode> toSelect = new List<TreeNode>();
+                        if (shiftDown && _supportMultiSelect)
+                        {
+                            toSelect.AddRange(Selection);
+                        }
                         if (keyUpArrow)
                         {
                             if (myIndex == 0)
                             {
                                 // Select parent
-                                toSelect = parentNode;
+                                if (toSelect.Contains(parentNode))
+                                    toSelect.Remove(node);
+                                else if (parentNode != null)
+                                    toSelect.Add(parentNode);
+                                _lastSelectedNode = parentNode;
                             }
                             else
                             {
                                 // Select previous parent child
-                                toSelect = nodeParent.GetChild(myIndex - 1) as TreeNode;
+                                var select = nodeParent.GetChild(myIndex - 1) as TreeNode;
 
                                 // Select last child if is valid and expanded and has any children
-                                if (toSelect != null && toSelect.IsExpanded && toSelect.HasAnyVisibleChild)
+                                if (select != null && select.IsExpanded && select.HasAnyVisibleChild)
                                 {
-                                    toSelect = toSelect.GetChild(toSelect.ChildrenCount - 1) as TreeNode;
+                                    select = select.GetChild(select.ChildrenCount - 1) as TreeNode;
                                 }
+
+                                if (select == null || toSelect.Contains(select))
+                                    toSelect.Remove(node);
+                                else
+                                    toSelect.Add(select);
+                                _lastSelectedNode = select;
                             }
                         }
                         // Down
@@ -432,32 +466,48 @@ namespace FlaxEditor.GUI.Tree
                             if (node.IsExpanded && node.HasAnyVisibleChild)
                             {
                                 // Select the first child
-                                toSelect = node.GetChild(0) as TreeNode;
+                                var select = node.GetChild(0) as TreeNode;
+                                if (select == null || toSelect.Contains(select))
+                                    toSelect.Remove(node);
+                                else
+                                    toSelect.Add(select);
+                                _lastSelectedNode = select;
                             }
                             else if (myIndex == nodeParent.ChildrenCount - 1)
                             {
                                 // Select next node after parent
-                                while (parentNode != null && toSelect == null)
+                                TreeNode select = null;
+                                while (parentNode != null && select == null)
                                 {
                                     int parentIndex = parentNode.IndexInParent;
                                     if (parentIndex != -1 && parentIndex < parentNode.Parent.ChildrenCount - 1)
                                     {
-                                        toSelect = parentNode.Parent.GetChild(parentIndex + 1) as TreeNode;
+                                        select = parentNode.Parent.GetChild(parentIndex + 1) as TreeNode;
                                     }
                                     parentNode = parentNode.Parent as TreeNode;
                                 }
+                                if (select == null || toSelect.Contains(select))
+                                    toSelect.Remove(node);
+                                else
+                                    toSelect.Add(select);
+                                _lastSelectedNode = select;
                             }
                             else
                             {
                                 // Select next parent child
-                                toSelect = nodeParent.GetChild(myIndex + 1) as TreeNode;
+                                var select = nodeParent.GetChild(myIndex + 1) as TreeNode;
+                                if (select == null || toSelect.Contains(select))
+                                    toSelect.Remove(node);
+                                else
+                                    toSelect.Add(select);
+                                _lastSelectedNode = select;
                             }
                         }
-                        if (toSelect != null && toSelect.AutoFocus)
+                        if (toSelect.Count > 0)
                         {
                             // Select
                             Select(toSelect);
-                            toSelect.Focus();
+                            _lastSelectedNode?.Focus();
                         }
 
                         // Reset time

Source/Editor/GUI/WindowDecorations.cs

@@ -0,0 +1,342 @@
+// Copyright (c) Wojciech Figat. All rights reserved.
+
+using System;
+using FlaxEditor.GUI.Docking;
+using FlaxEditor.Options;
+using FlaxEngine;
+using FlaxEngine.GUI;
+
+namespace FlaxEditor.GUI;
+
+/// <summary>
+/// Represents the title bar of the window with buttons.
+/// </summary>
+/// <seealso cref="FlaxEngine.GUI.ContainerControl" />
+public class WindowDecorations : ContainerControl
+{
+    private Image _icon;
+    private Label _title;
+    private Button _closeButton;
+    private Button _minimizeButton;
+    private Button _maximizeButton;
+    private LocalizedString _charChromeRestore, _charChromeMaximize;
+    private Window _window;
+
+    /// <summary>
+    /// The title label in the title bar.
+    /// </summary>
+    public Label Title => _title;
+    
+    /// <summary>
+    /// The icon used in the title bar.
+    /// </summary>
+    public Image Icon => _icon;
+    
+    /// <summary>
+    /// The tooltip shown when hovering over the icon.
+    /// </summary>
+    public string IconTooltipText
+    {
+        get => _icon?.TooltipText ?? null;
+        set
+        {
+            if (_icon != null)
+                _icon.TooltipText = value;
+        }
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="WindowDecorations"/> class.
+    /// </summary>
+    /// <param name="window">The window.</param>
+    /// <param name="iconOnly">When set, omit drawing title and buttons.</param>
+    public WindowDecorations(RootControl window, bool iconOnly = false)
+    : base(0, 0, 0, 20)
+    {
+        _window = window.RootWindow.Window;
+        
+        AutoFocus = false;
+        AnchorPreset = AnchorPresets.HorizontalStretchTop;
+        BackgroundColor = Color.Transparent;
+
+        var windowIcon = FlaxEngine.Content.LoadAsyncInternal<Texture>(EditorAssets.WindowIcon);
+
+        _icon = new Image
+        {
+            Margin = new Margin(4, 4, 4, 4),
+            Brush = new TextureBrush(windowIcon),
+            Color = Style.Current.Foreground,
+            BackgroundColor = Style.Current.LightBackground,
+            KeepAspectRatio = false,
+            Parent = this,
+        };
+
+        if (!iconOnly)
+        {
+            _icon.Margin = new Margin(6, 6, 6, 6);
+            Height = 28;
+            
+            _window.HitTest += OnHitTest;
+            _window.Closed += OnWindowClosed;
+            
+            FontAsset windowIconsFont = FlaxEngine.Content.LoadAsyncInternal<FontAsset>(EditorAssets.WindowIconsFont);
+            Font iconFont = windowIconsFont?.CreateFont(9);
+            
+            _title = new Label(0, 0, Width, Height)
+            {
+                Text = _window.Title,
+                HorizontalAlignment = TextAlignment.Center,
+                VerticalAlignment = TextAlignment.Center,
+                ClipText = true,
+                TextColor = Style.Current.ForegroundGrey,
+                TextColorHighlighted = Style.Current.ForegroundGrey,
+                BackgroundColor = Style.Current.LightBackground,
+                Parent = this,
+            };
+
+            _closeButton = new Button
+            {
+                Text = ((char)EditorAssets.SegMDL2Icons.ChromeClose).ToString(),
+                Font = new FontReference(iconFont),
+                BackgroundColor = Style.Current.LightBackground,
+                BorderColor = Color.Transparent,
+                BorderColorHighlighted = Color.Transparent,
+                BorderColorSelected = Color.Transparent,
+                TextColor = Style.Current.Foreground,
+                Width = 46,
+                BackgroundColorHighlighted = Color.Red,
+                BackgroundColorSelected = Color.Red.RGBMultiplied(1.3f),
+                Parent = this,
+            };
+            _closeButton.Clicked += () => _window.Close(ClosingReason.User);
+
+            _minimizeButton = new Button
+            {
+                Text = ((char)EditorAssets.SegMDL2Icons.ChromeMinimize).ToString(),
+                Font = new FontReference(iconFont),
+                BackgroundColor = Style.Current.LightBackground,
+                BorderColor = Color.Transparent,
+                BorderColorHighlighted = Color.Transparent,
+                BorderColorSelected = Color.Transparent,
+                TextColor = Style.Current.Foreground,
+                Width = 46,
+                BackgroundColorHighlighted = Style.Current.LightBackground.RGBMultiplied(1.3f),
+                Parent = this,
+            };
+            _minimizeButton.Clicked += () => _window.Minimize();
+
+            _maximizeButton = new Button
+            {
+                Text = ((char)(_window.IsMaximized ? EditorAssets.SegMDL2Icons.ChromeRestore : EditorAssets.SegMDL2Icons.ChromeMaximize)).ToString(),
+                Font = new FontReference(iconFont),
+                BackgroundColor = Style.Current.LightBackground,
+                BorderColor = Color.Transparent,
+                BorderColorHighlighted = Color.Transparent,
+                BorderColorSelected = Color.Transparent,
+                TextColor = Style.Current.Foreground,
+                Width = 46,
+                BackgroundColorHighlighted = Style.Current.LightBackground.RGBMultiplied(1.3f),
+                Parent = this,
+            };
+            _maximizeButton.Clicked += () =>
+            {
+                if (_window.IsMaximized)
+                    _window.Restore();
+                else
+                    _window.Maximize();
+            };
+
+            _charChromeRestore = ((char)EditorAssets.SegMDL2Icons.ChromeRestore).ToString();
+            _charChromeMaximize = ((char)EditorAssets.SegMDL2Icons.ChromeMaximize).ToString();
+        }
+    }
+    
+    /// <inheritdoc />
+    public override void Update(float deltaTime)
+    {
+        base.Update(deltaTime);
+
+        if (_maximizeButton != null)
+        {
+            var maximizeText = _window.IsMaximized ? _charChromeRestore : _charChromeMaximize;
+            if (_maximizeButton.Text != maximizeText)
+                _maximizeButton.Text = maximizeText;
+        }
+    }
+
+    private void OnWindowClosed()
+    {
+        if (_window != null)
+        {
+            _window.HitTest -= OnHitTest;
+            _window = null;
+        }
+    }
+
+    /// <summary>
+    /// Perform hit test on the window.
+    /// </summary>
+    /// <param name="mouse">The mouse position</param>
+    /// <returns>The hit code for given position.</returns>
+    protected virtual WindowHitCodes OnHitTest(ref Float2 mouse)
+    {
+        if (_window.IsMinimized)
+            return WindowHitCodes.NoWhere;
+
+        var dpiScale = _window.DpiScale;
+        var pos = _window.ScreenToClient(mouse * dpiScale); // pos is not DPI adjusted
+        if (!_window.IsMaximized)
+        {
+            var winSize = _window.Size;
+
+            // Distance from which the mouse is considered to be on the border/corner
+            float distance = 5.0f * dpiScale;
+
+            if (pos.Y > winSize.Y - distance && pos.X < distance)
+                return WindowHitCodes.BottomLeft;
+
+            if (pos.X > winSize.X - distance && pos.Y > winSize.Y - distance)
+                return WindowHitCodes.BottomRight;
+
+            if (pos.Y < distance && pos.X < distance)
+                return WindowHitCodes.TopLeft;
+
+            if (pos.Y < distance && pos.X > winSize.X - distance)
+                return WindowHitCodes.TopRight;
+
+            if (pos.X > winSize.X - distance)
+                return WindowHitCodes.Right;
+
+            if (pos.X < distance)
+                return WindowHitCodes.Left;
+
+            if (pos.Y < distance)
+                return WindowHitCodes.Top;
+
+            if (pos.Y > winSize.Y - distance)
+                return WindowHitCodes.Bottom;
+        }
+        
+        var controlUnderMouse = GetChildAt(pos, control => control != _title);
+        if (_title.Bounds.Contains(pos) && controlUnderMouse == null)
+            return WindowHitCodes.Caption;
+
+        return WindowHitCodes.Client;
+    }
+    
+    /// <inheritdoc />
+    public override bool OnMouseDoubleClick(Float2 location, MouseButton button)
+    {
+        // These may not work with main window due to SDL not passing mouse events
+        // when interacting with hit tests on caption area...
+        
+        if (Title.Bounds.Contains(location) && button == MouseButton.Left)
+        {
+            if (_window.IsMaximized)
+                _window.Restore();
+            else
+                _window.Maximize();
+            return true;
+        }
+        else if (Icon.Bounds.Contains(location) && button == MouseButton.Left)
+        {
+            _window.Close(ClosingReason.User);
+            return true;
+        }
+        return base.OnMouseDoubleClick(location, button);
+    }
+
+    /// <inheritdoc />
+    protected override void PerformLayoutAfterChildren()
+    {
+        // Calculate extents for title bounds area excluding the icon and main menu area
+        float x = 0;
+        
+        // Icon
+        if (_icon != null)
+        {
+            _icon.X = x;
+            _icon.Size = new Float2(Height);
+            x += _icon.Width;
+        }
+
+        // Main menu if present
+        if (Parent.GetChild<MainMenu>() is MainMenu mainMenu)
+        {
+            for (int i = 0; i < mainMenu.Children.Count; i++)
+            {
+                var c = mainMenu.Children[i];
+                if (c is MainMenuButton b && c.Visible)
+                {
+                    b.Bounds = new Rectangle(x, 0, b.Width, Height);
+                    x += b.Width;
+                }
+            }
+        }
+     
+        // Buttons
+        float rightMostButtonX = Width;
+        if (_closeButton != null)
+        {
+            _closeButton.Height = Height;
+            _closeButton.X = rightMostButtonX - _closeButton.Width;
+            rightMostButtonX = _closeButton.X;
+        }
+        if (_maximizeButton != null)
+        {
+            _maximizeButton.Height = Height;
+            _maximizeButton.X = rightMostButtonX - _maximizeButton.Width;
+            rightMostButtonX = _maximizeButton.X;
+        }
+        if (_minimizeButton != null)
+        {
+            _minimizeButton.Height = Height;
+            _minimizeButton.X = rightMostButtonX - _minimizeButton.Width;
+            rightMostButtonX = _minimizeButton.X;
+        }
+
+        // Title
+        if (_title != null)
+        {
+            _title.Text = _window.Title;
+            _title.Bounds = new Rectangle(x, 0, rightMostButtonX - x, Height);
+        }
+    }
+    
+    /// <inheritdoc />
+    public override void Draw()
+    {
+        base.Draw();
+        DrawBorders();
+    }
+
+    /// <summary>
+    /// Draw borders around the window.
+    /// </summary>
+    public virtual void DrawBorders()
+    {
+        var win = RootWindow.Window;
+        if (win.IsMaximized)
+            return;
+
+        if (Editor.Instance.UI.StatusBar == null)
+            return;
+        
+        const float thickness = 1.0f;
+        Color color = Editor.Instance.UI.StatusBar.StatusColor;
+        Rectangle rect = new Rectangle(thickness * 0.5f, thickness * 0.5f, Parent.Width - thickness, Parent.Height - thickness);
+        Render2D.DrawRectangle(rect, color);
+    }
+
+    /// <inheritdoc />
+    public override void OnDestroy()
+    {
+        base.OnDestroy();
+
+        if (_window != null)
+        {
+            _window.Closed -= OnWindowClosed;
+            OnWindowClosed();
+        }
+    }
+}

Source/Editor/Gizmo/TransformGizmoBase.Draw.cs

@@ -1,9 +1,7 @@
 // Copyright (c) Wojciech Figat. All rights reserved.
 
 using FlaxEditor.Options;
-using FlaxEditor.SceneGraph;
 using FlaxEngine;
-using System;
 
 namespace FlaxEditor.Gizmo
 {
@@ -21,12 +19,16 @@ namespace FlaxEditor.Gizmo
         private MaterialInstance _materialAxisY;
         private MaterialInstance _materialAxisZ;
         private MaterialInstance _materialAxisFocus;
-        private MaterialInstance _materialAxisLocked;
         private MaterialBase _materialSphere;
 
         // Material Parameter Names
-        const String _brightnessParamName = "Brightness";
-        const String _opacityParamName = "Opacity";
+        private const string _brightnessParamName = "Brightness";
+        private const string _opacityParamName = "Opacity";
+
+        /// <summary>
+        /// Used for example when the selection can't be moved because one actor is static.
+        /// </summary>
+        private bool _isDisabled;
 
         private void InitDrawing()
         {
@@ -42,7 +44,6 @@ namespace FlaxEditor.Gizmo
             _materialAxisY = FlaxEngine.Content.LoadAsyncInternal<MaterialInstance>("Editor/Gizmo/MaterialAxisY");
             _materialAxisZ = FlaxEngine.Content.LoadAsyncInternal<MaterialInstance>("Editor/Gizmo/MaterialAxisZ");
             _materialAxisFocus = FlaxEngine.Content.LoadAsyncInternal<MaterialInstance>("Editor/Gizmo/MaterialAxisFocus");
-            _materialAxisLocked = FlaxEngine.Content.LoadAsyncInternal<MaterialInstance>("Editor/Gizmo/MaterialAxisLocked");
             _materialSphere = FlaxEngine.Content.LoadAsyncInternal<MaterialInstance>("Editor/Gizmo/MaterialSphere");
 
             // Ensure that every asset was loaded
@@ -67,17 +68,42 @@ namespace FlaxEditor.Gizmo
 
         private void OnEditorOptionsChanged(EditorOptions options)
         {
-            float brightness = options.Visual.TransformGizmoBrightness;
-            _materialAxisX.SetParameterValue(_brightnessParamName, brightness);
-            _materialAxisY.SetParameterValue(_brightnessParamName, brightness);
-            _materialAxisZ.SetParameterValue(_brightnessParamName, brightness);
-            _materialAxisLocked.SetParameterValue(_brightnessParamName, brightness);
-            
+            UpdateGizmoBrightness(options);
+
             float opacity = options.Visual.TransformGizmoOpacity;
             _materialAxisX.SetParameterValue(_opacityParamName, opacity);
             _materialAxisY.SetParameterValue(_opacityParamName, opacity);
             _materialAxisZ.SetParameterValue(_opacityParamName, opacity);
-            _materialAxisLocked.SetParameterValue(_opacityParamName, opacity);
+        }
+
+        private void UpdateGizmoBrightness(EditorOptions options)
+        {
+            _isDisabled = ShouldGizmoBeLocked();
+
+            float brightness = _isDisabled ? options.Visual.TransformGizmoBrightnessDisabled : options.Visual.TransformGizmoBrightness;
+            if (Mathf.NearEqual(brightness, (float)_materialAxisX.GetParameterValue(_brightnessParamName)))
+                return;
+            _materialAxisX.SetParameterValue(_brightnessParamName, brightness);
+            _materialAxisY.SetParameterValue(_brightnessParamName, brightness);
+            _materialAxisZ.SetParameterValue(_brightnessParamName, brightness);
+        }
+
+        private bool ShouldGizmoBeLocked()
+        {
+            bool gizmoLocked = false;
+            if (Editor.Instance.StateMachine.IsPlayMode && Owner is Viewport.EditorGizmoViewport)
+            {
+                // Block editing static scene objects in main view during play mode
+                foreach (var obj in Editor.Instance.SceneEditing.Selection)
+                {
+                    if (obj.CanTransform == false)
+                    {
+                        gizmoLocked = true;
+                        break;
+                    }
+                }
+            }
+            return gizmoLocked;
         }
 
         /// <inheritdoc />
@@ -88,20 +114,8 @@ namespace FlaxEditor.Gizmo
             if (!_modelCube || !_modelCube.IsLoaded)
                 return;
 
-            // Find out if any of the selected objects can not be moved
-            bool gizmoLocked = false;
-            if (Editor.Instance.StateMachine.IsPlayMode)
-            {
-                for (int i = 0; i < SelectionCount; i++)
-                {
-                    var obj = GetSelectedObject(i);
-                    if (obj.CanTransform == false)
-                    {
-                        gizmoLocked = true;
-                        break;
-                    }
-                }
-            }
+            // Update the gizmo brightness every frame to ensure it updates correctly
+            UpdateGizmoBrightness(Editor.Instance.Options.Options);
 
             // As all axisMesh have the same pivot, add a little offset to the x axisMesh, this way SortDrawCalls is able to sort the draw order
             // https://github.com/FlaxEngine/FlaxEngine/issues/680
@@ -136,37 +150,37 @@ namespace FlaxEditor.Gizmo
                 // X axis
                 Matrix.RotationY(-Mathf.PiOverTwo, out m2);
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance xAxisMaterialTransform = gizmoLocked ? _materialAxisLocked : (isXAxis ? _materialAxisFocus : _materialAxisX);
+                MaterialInstance xAxisMaterialTransform = (isXAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisX;
                 transAxisMesh.Draw(ref renderContext, xAxisMaterialTransform, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Y axis
                 Matrix.RotationX(Mathf.PiOverTwo, out m2);
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance yAxisMaterialTransform = gizmoLocked ? _materialAxisLocked : (isYAxis ? _materialAxisFocus : _materialAxisY);
+                MaterialInstance yAxisMaterialTransform = (isYAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisY;
                 transAxisMesh.Draw(ref renderContext, yAxisMaterialTransform, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Z axis
                 Matrix.RotationX(Mathf.Pi, out m2);
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance zAxisMaterialTransform = gizmoLocked ? _materialAxisLocked : (isZAxis ? _materialAxisFocus : _materialAxisZ);
+                MaterialInstance zAxisMaterialTransform = (isZAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisZ;
                 transAxisMesh.Draw(ref renderContext, zAxisMaterialTransform, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // XY plane
                 m2 = Matrix.Transformation(new Vector3(boxSize, boxSize * 0.1f, boxSize), Quaternion.RotationX(Mathf.PiOverTwo), new Vector3(boxSize * boxScale, boxSize * boxScale, 0.0f));
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance xyPlaneMaterialTransform = gizmoLocked ? _materialAxisLocked : (_activeAxis == Axis.XY ? _materialAxisFocus : _materialAxisX);
+                MaterialInstance xyPlaneMaterialTransform = (_activeAxis == Axis.XY && !_isDisabled) ? _materialAxisFocus : _materialAxisX;
                 cubeMesh.Draw(ref renderContext, xyPlaneMaterialTransform, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // ZX plane
                 m2 = Matrix.Transformation(new Vector3(boxSize, boxSize * 0.1f, boxSize), Quaternion.Identity, new Vector3(boxSize * boxScale, 0.0f, boxSize * boxScale));
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance zxPlaneMaterialTransform = gizmoLocked ? _materialAxisLocked : (_activeAxis == Axis.ZX ? _materialAxisFocus : _materialAxisY);
+                MaterialInstance zxPlaneMaterialTransform = (_activeAxis == Axis.ZX && !_isDisabled) ? _materialAxisFocus : _materialAxisY;
                 cubeMesh.Draw(ref renderContext, zxPlaneMaterialTransform, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // YZ plane
                 m2 = Matrix.Transformation(new Vector3(boxSize, boxSize * 0.1f, boxSize), Quaternion.RotationZ(Mathf.PiOverTwo), new Vector3(0.0f, boxSize * boxScale, boxSize * boxScale));
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance yzPlaneMaterialTransform = gizmoLocked ? _materialAxisLocked : (_activeAxis == Axis.YZ ? _materialAxisFocus : _materialAxisZ);
+                MaterialInstance yzPlaneMaterialTransform = (_activeAxis == Axis.YZ && !_isDisabled) ? _materialAxisFocus : _materialAxisZ;
                 cubeMesh.Draw(ref renderContext, yzPlaneMaterialTransform, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Center sphere
@@ -186,17 +200,17 @@ namespace FlaxEditor.Gizmo
                 // X axis
                 Matrix.RotationZ(Mathf.PiOverTwo, out m2);
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance xAxisMaterialRotate = gizmoLocked ? _materialAxisLocked : (isXAxis ? _materialAxisFocus : _materialAxisX);
+                MaterialInstance xAxisMaterialRotate = (isXAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisX;
                 rotationAxisMesh.Draw(ref renderContext, xAxisMaterialRotate, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Y axis
-                MaterialInstance yAxisMaterialRotate = gizmoLocked ? _materialAxisLocked : (isYAxis ? _materialAxisFocus : _materialAxisY);
+                MaterialInstance yAxisMaterialRotate = (isYAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisY;
                 rotationAxisMesh.Draw(ref renderContext, yAxisMaterialRotate, ref m1, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Z axis
                 Matrix.RotationX(-Mathf.PiOverTwo, out m2);
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance zAxisMaterialRotate = gizmoLocked ? _materialAxisLocked : (isZAxis ? _materialAxisFocus : _materialAxisZ);
+                MaterialInstance zAxisMaterialRotate = (isZAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisZ;
                 rotationAxisMesh.Draw(ref renderContext, zAxisMaterialRotate, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Center box
@@ -216,37 +230,37 @@ namespace FlaxEditor.Gizmo
                 // X axis
                 Matrix.RotationY(-Mathf.PiOverTwo, out m2);
                 Matrix.Multiply(ref m2, ref mx1, out m3);
-                MaterialInstance xAxisMaterialRotate = gizmoLocked ? _materialAxisLocked : (isXAxis ? _materialAxisFocus : _materialAxisX);
+                MaterialInstance xAxisMaterialRotate = (isXAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisX;
                 scaleAxisMesh.Draw(ref renderContext, xAxisMaterialRotate, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Y axis
                 Matrix.RotationX(Mathf.PiOverTwo, out m2);
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance yAxisMaterialRotate = gizmoLocked ? _materialAxisLocked : (isYAxis ? _materialAxisFocus : _materialAxisY);
+                MaterialInstance yAxisMaterialRotate = (isYAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisY;
                 scaleAxisMesh.Draw(ref renderContext, yAxisMaterialRotate, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Z axis
                 Matrix.RotationX(Mathf.Pi, out m2);
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance zAxisMaterialRotate = gizmoLocked ? _materialAxisLocked : (isZAxis ? _materialAxisFocus : _materialAxisZ);
+                MaterialInstance zAxisMaterialRotate = (isZAxis && !_isDisabled) ? _materialAxisFocus : _materialAxisZ;
                 scaleAxisMesh.Draw(ref renderContext, zAxisMaterialRotate, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // XY plane
                 m2 = Matrix.Transformation(new Vector3(boxSize, boxSize * 0.1f, boxSize), Quaternion.RotationX(Mathf.PiOverTwo), new Vector3(boxSize * boxScale, boxSize * boxScale, 0.0f));
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance xyPlaneMaterialScale = gizmoLocked ? _materialAxisLocked : (_activeAxis == Axis.XY ? _materialAxisFocus : _materialAxisX);
+                MaterialInstance xyPlaneMaterialScale = (_activeAxis == Axis.XY && !_isDisabled) ? _materialAxisFocus : _materialAxisX;
                 cubeMesh.Draw(ref renderContext, xyPlaneMaterialScale, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // ZX plane
                 m2 = Matrix.Transformation(new Vector3(boxSize, boxSize * 0.1f, boxSize), Quaternion.Identity, new Vector3(boxSize * boxScale, 0.0f, boxSize * boxScale));
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance zxPlaneMaterialScale = gizmoLocked ? _materialAxisLocked : (_activeAxis == Axis.ZX ? _materialAxisFocus : _materialAxisZ);
+                MaterialInstance zxPlaneMaterialScale = (_activeAxis == Axis.ZX && !_isDisabled) ? _materialAxisFocus : _materialAxisZ;
                 cubeMesh.Draw(ref renderContext, zxPlaneMaterialScale, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // YZ plane
                 m2 = Matrix.Transformation(new Vector3(boxSize, boxSize * 0.1f, boxSize), Quaternion.RotationZ(Mathf.PiOverTwo), new Vector3(0.0f, boxSize * boxScale, boxSize * boxScale));
                 Matrix.Multiply(ref m2, ref m1, out m3);
-                MaterialInstance yzPlaneMaterialScale = gizmoLocked ? _materialAxisLocked : (_activeAxis == Axis.YZ ? _materialAxisFocus : _materialAxisY);
+                MaterialInstance yzPlaneMaterialScale = (_activeAxis == Axis.YZ && !_isDisabled) ? _materialAxisFocus : _materialAxisY;
                 cubeMesh.Draw(ref renderContext, yzPlaneMaterialScale, ref m3, StaticFlags.None, true, DrawPass.Default, 0.0f, sortOrder);
 
                 // Center box

Source/Editor/Gizmo/UIEditorGizmo.cs

@@ -155,6 +155,16 @@ namespace FlaxEditor
         private List<Widget> _widgets;
         private Widget _activeWidget;
 
+        /// <summary>
+        /// Sets the view size.
+        /// </summary>
+        /// <param name="size">The new size.</param>
+        public void SetViewSize(Float2 size)
+        {
+            _view.Size = size;
+            _view.PerformLayout();
+        }
+
         /// <summary>
         /// True if enable displaying UI editing background and grid elements.
         /// </summary>

Source/Editor/Managed/ManagedEditor.Internal.cpp

@@ -402,10 +402,11 @@ DEFINE_INTERNAL_CALL(void) EditorInternal_RunVisualScriptBreakpointLoopTick(floa
                 break;
             }
         }
+        WindowsManager::WindowsLocker.Unlock();
         for (const auto& e : inputEvents)
         {
             auto window = e.Target ? e.Target : defaultWindow;
-            if (!window)
+            if (!window || window->IsClosed())
                 continue;
             switch (e.Type)
             {
@@ -435,12 +436,14 @@ DEFINE_INTERNAL_CALL(void) EditorInternal_RunVisualScriptBreakpointLoopTick(floa
             case InputDevice::EventType::MouseMove:
                 window->OnMouseMove(window->ScreenToClient(e.MouseData.Position));
                 break;
+            case InputDevice::EventType::MouseMoveRelative:
+                window->OnMouseMoveRelative(e.MouseMovementData.PositionRelative);
+                break;
             case InputDevice::EventType::MouseLeave:
                 window->OnMouseLeave();
                 break;
             }
         }
-        WindowsManager::WindowsLocker.Unlock();
     }
     WindowsManager::WindowsLocker.Lock();
     Array<Window*, InlinedAllocation<32>> windows;

Source/Editor/Managed/ManagedEditor.cpp

@@ -11,6 +11,7 @@
 #include "Engine/Scripting/ManagedCLR/MClass.h"
 #include "Engine/Scripting/ManagedCLR/MException.h"
 #include "Engine/Scripting/Internal/MainThreadManagedInvokeAction.h"
+#include "Engine/Platform/WindowsManager.h"
 #include "Engine/Content/Assets/VisualScript.h"
 #include "Engine/Content/Content.h"
 #include "Engine/CSG/CSGBuilder.h"
@@ -622,6 +623,14 @@ void ManagedEditor::WipeOutLeftoverSceneObjects()
         ObjectsRemovalService::Flush();
 }
 
+Array<Window*> ManagedEditor::GetWindows()
+{
+    WindowsManager::WindowsLocker.Lock();
+    auto result = WindowsManager::Windows;
+    WindowsManager::WindowsLocker.Unlock();
+    return result;
+}
+
 void ManagedEditor::OnEditorAssemblyLoaded(MAssembly* assembly)
 {
     ASSERT(!HasManagedInstance());

Source/Editor/Managed/ManagedEditor.h

@@ -259,6 +259,7 @@ public:
     API_FUNCTION(Internal) static Array<VisualScriptLocal> GetVisualScriptLocals();
     API_FUNCTION(Internal) static bool EvaluateVisualScriptLocal(VisualScript* script, API_PARAM(Ref) VisualScriptLocal& local);
     API_FUNCTION(Internal) static void WipeOutLeftoverSceneObjects();
+    API_FUNCTION(Internal) static Array<Window*> GetWindows();
 
 private:
     void OnEditorAssemblyLoaded(MAssembly* assembly);

Source/Editor/Modules/ContentDatabaseModule.cs

@@ -1013,7 +1013,7 @@ namespace FlaxEditor.Modules
                     ContentItem item;
                     if (path.EndsWith(".cs"))
                         item = new CSharpScriptItem(path);
-                    else if (path.EndsWith(".cpp") || path.EndsWith(".h"))
+                    else if (path.EndsWith(".cpp") || path.EndsWith(".h") || path.EndsWith(".c") || path.EndsWith(".hpp"))
                         item = new CppScriptItem(path);
                     else if (path.EndsWith(".shader") || path.EndsWith(".hlsl"))
                         item = new ShaderSourceItem(path);

Source/Editor/Modules/ContentImportingModule.cs

@@ -222,7 +222,7 @@ namespace FlaxEditor.Modules
                 outputExtension = extension;
 
                 // Check if can place source files here
-                if (!targetLocation.CanHaveScripts && (extension == ".cs" || extension == ".cpp" || extension == ".h"))
+                if (!targetLocation.CanHaveScripts && (extension == ".cs" || extension == ".cpp" || extension == ".h" || extension == ".c" || extension == ".hpp"))
                 {
                     // Error
                     Editor.LogWarning(string.Format("Cannot import \'{0}\' to \'{1}\'. The target directory cannot have scripts.", inputPath, targetLocation.Node.Path));

Source/Editor/Modules/PrefabsModule.cs

@@ -254,18 +254,29 @@ namespace FlaxEditor.Modules
             PrefabApplying?.Invoke(prefab, instance);
 
             // When applying changes to prefab from actor in level ignore it's root transformation (see ActorEditor.ProcessDiff)
+            Actor prefabRoot = null;
             var originalTransform = instance.LocalTransform;
             var originalName = instance.Name;
-            if (instance.IsPrefabRoot && instance.HasScene)
+            if (instance.HasScene)
             {
-                instance.LocalTransform = prefab.GetDefaultInstance().Transform;
-                instance.Name = prefab.GetDefaultInstance().Name;
+                prefabRoot = instance.GetPrefabRoot();
+                if (prefabRoot != null && prefabRoot.IsPrefabRoot && instance.HasScene)
+                {
+                    var defaultInstance = prefab.GetDefaultInstance();
+                    originalTransform = prefabRoot.LocalTransform;
+                    originalName = prefabRoot.Name;
+                    prefabRoot.LocalTransform = defaultInstance.Transform;
+                    prefabRoot.Name = defaultInstance.Name;
+                }
             }
 
             // Call backend
             var failed = PrefabManager.Internal_ApplyAll(FlaxEngine.Object.GetUnmanagedPtr(instance));
-            instance.LocalTransform = originalTransform;
-            instance.Name = originalName;
+            if (prefabRoot != null)
+            {
+                prefabRoot.LocalTransform = originalTransform;
+                prefabRoot.Name = originalName;
+            }
             if (failed)
                 throw new Exception("Failed to apply the prefab. See log to learn more.");
 

Source/Editor/Modules/SceneEditingModule.cs

@@ -673,6 +673,7 @@ namespace FlaxEditor.Modules
                 pasteAction.Do(out _, out var nodeParents);
 
                 // Select spawned objects (parents only)
+                newSelection.Clear();
                 newSelection.AddRange(nodeParents);
                 var selectAction = new SelectionChangeAction(Selection.ToArray(), newSelection.ToArray(), OnSelectionUndo);
                 selectAction.Do();

Source/Editor/Modules/SceneModule.cs

@@ -568,6 +568,10 @@ namespace FlaxEditor.Modules
                 return;
             }
 
+            // Skip if already added
+            if (SceneGraphFactory.Nodes.ContainsKey(actor.ID))
+                return;
+
             var node = SceneGraphFactory.BuildActorNode(actor);
             if (node != null)
             {

Source/Editor/Modules/SimulationModule.cs

@@ -267,7 +267,7 @@ namespace FlaxEditor.Modules
         }
 
         /// <inheritdoc />
-        public override void OnPlayBegin()
+        public override void OnPlayBeginning()
         {
             Editor.Windows.FlashMainWindow();
 

Source/Editor/Modules/SourceCodeEditing/InBuildSourceCodeEditor.cs

@@ -54,6 +54,9 @@ namespace FlaxEditor.Modules.SourceCodeEditing
             case CodeEditorTypes.VS2022:
                 Name = "Visual Studio 2022";
                 break;
+            case CodeEditorTypes.VS2026:
+                Name = "Visual Studio 2026";
+                break;
             case CodeEditorTypes.VSCode:
                 Name = "Visual Studio Code";
                 break;
@@ -110,6 +113,7 @@ namespace FlaxEditor.Modules.SourceCodeEditing
             case CodeEditorTypes.VS2017:
             case CodeEditorTypes.VS2019:
             case CodeEditorTypes.VS2022:
+            case CodeEditorTypes.VS2026:
                 // TODO: finish dynamic files adding to the project
                 //Editor.Instance.ProgressReporting.GenerateScriptsProjectFiles.RunAsync();
                 break;

Source/Editor/Modules/UIModule.cs

@@ -16,7 +16,6 @@ using FlaxEditor.Windows;
 using FlaxEngine;
 using FlaxEngine.GUI;
 using FlaxEngine.Json;
-using DockHintWindow = FlaxEditor.GUI.Docking.DockHintWindow;
 using MasterDockPanel = FlaxEditor.GUI.Docking.MasterDockPanel;
 using FlaxEditor.Content.Settings;
 using FlaxEditor.Options;
@@ -29,6 +28,40 @@ namespace FlaxEditor.Modules
     /// <seealso cref="FlaxEditor.Modules.EditorModule" />
     public sealed class UIModule : EditorModule
     {
+        private class MainWindowDecorations : WindowDecorations
+        {
+            public MainWindowDecorations(RootControl window, bool iconOnly) 
+            : base(window, iconOnly)
+            {
+            }
+
+            /// <inheritdoc />
+            public override bool OnKeyDown(KeyboardKeys key)
+            {
+                if (base.OnKeyDown(key))
+                    return true;
+
+                // Fallback to the edit window for shortcuts
+                var editor = Editor.Instance;
+                return editor.Windows.EditWin.InputActions.Process(editor, this, key);
+            }
+            
+            /// <inheritdoc />
+            public override void DrawBorders()
+            {
+                // Draw main window borders if using a custom style
+                var win = RootWindow.Window;
+                if (win.IsMaximized)
+                    return;
+
+                var color = Editor.Instance.UI.StatusBar.StatusColor;
+                var rect = new Rectangle(0.5f, 0.5f, Parent.Width - 1.0f, Parent.Height - 1.0f - StatusBar.DefaultHeight);
+                Render2D.DrawLine(rect.UpperLeft, rect.UpperRight, color);
+                Render2D.DrawLine(rect.UpperLeft, rect.BottomLeft, color);
+                Render2D.DrawLine(rect.UpperRight, rect.BottomRight, color);
+            }
+        }
+        
         private Label _progressLabel;
         private ProgressBar _progressBar;
         private Button _outputLogButton;
@@ -37,6 +70,53 @@ namespace FlaxEditor.Modules
         private bool _progressFailed;
 
         ContextMenuSingleSelectGroup<int> _numberOfClientsGroup = new ContextMenuSingleSelectGroup<int>();
+        
+        /// <summary>
+        /// Defines a viewport scaling option.
+        /// </summary>
+        public class ViewportScaleOption
+        {
+            /// <summary>
+            /// Defines the viewport scale type.
+            /// </summary>
+            public enum ViewportScaleType
+            {
+                /// <summary>
+                /// Resolution.
+                /// </summary>
+                Resolution = 0,
+
+                /// <summary>
+                /// Aspect Ratio.
+                /// </summary>
+                Aspect = 1,
+            }
+            
+            /// <summary>
+            /// The name.
+            /// </summary>
+            public string Label;
+
+            /// <summary>
+            /// The Type of scaling to do.
+            /// </summary>
+            public ViewportScaleType ScaleType;
+
+            /// <summary>
+            /// The width and height to scale by.
+            /// </summary>
+            public Int2 Size;
+        }
+ 
+        /// <summary>
+        /// The default viewport scaling options.
+        /// </summary>
+        public List<ViewportScaleOption> DefaultViewportScaleOptions = new List<ViewportScaleOption>();
+
+        /// <summary>
+        /// The user defined viewport scaling options.
+        /// </summary>
+        public List<ViewportScaleOption> CustomViewportScaleOptions = new List<ViewportScaleOption>();
 
         private ContextMenuButton _menuFileSaveScenes;
         private ContextMenuButton _menuFileReloadScenes;
@@ -97,6 +177,11 @@ namespace FlaxEditor.Modules
         /// </summary>
         public MainMenu MainMenu;
 
+        /// <summary>
+        /// The window decorations (title bar with buttons)
+        /// </summary>
+        public WindowDecorations WindowDecorations;
+
         /// <summary>
         /// The tool strip control.
         /// </summary>
@@ -371,25 +456,70 @@ namespace FlaxEditor.Modules
 
             // Update window background
             mainWindow.BackgroundColor = Style.Current.Background;
+            
+            InitViewportScaleOptions();
 
             InitSharedMenus();
             InitMainMenu(mainWindow);
             InitToolstrip(mainWindow);
             InitStatusBar(mainWindow);
             InitDockPanel(mainWindow);
+            InitWindowDecorations(mainWindow);
 
             Editor.Options.OptionsChanged += OnOptionsChanged;
+            
+            mainWindow.PerformLayout(true);
+        }
 
-            // Add dummy control for drawing the main window borders if using a custom style
-#if PLATFORM_WINDOWS
-            if (!Editor.Options.Options.Interface.UseNativeWindowSystem)
-#endif
+        private void InitViewportScaleOptions()
+        {
+            if (DefaultViewportScaleOptions.Count == 0)
             {
-                mainWindow.AddChild(new CustomWindowBorderControl
+                DefaultViewportScaleOptions.Add(new ViewportScaleOption
                 {
-                    Size = Float2.Zero,
+                    Label = "Free Aspect",
+                    ScaleType = ViewportScaleOption.ViewportScaleType.Aspect,
+                    Size = new Int2(1, 1),
+                });
+                DefaultViewportScaleOptions.Add(new ViewportScaleOption
+                {
+                    Label = "16:9 Aspect",
+                    ScaleType = ViewportScaleOption.ViewportScaleType.Aspect,
+                    Size = new Int2(16, 9),
+                });
+                DefaultViewportScaleOptions.Add(new ViewportScaleOption
+                {
+                    Label = "16:10 Aspect",
+                    ScaleType = ViewportScaleOption.ViewportScaleType.Aspect,
+                    Size = new Int2(16, 10),
+                });
+                DefaultViewportScaleOptions.Add(new ViewportScaleOption
+                {
+                    Label = "1920x1080 Resolution (Full HD)",
+                    ScaleType = ViewportScaleOption.ViewportScaleType.Resolution,
+                    Size = new Int2(1920, 1080),
+                });
+                DefaultViewportScaleOptions.Add(new ViewportScaleOption
+                {
+                    Label = "2560x1440 Resolution (2K)",
+                    ScaleType = ViewportScaleOption.ViewportScaleType.Resolution,
+                    Size = new Int2(2560, 1440),
                 });
             }
+            
+            if (Editor.Instance.ProjectCache.TryGetCustomData("CustomViewportScalingOptions", out string data))
+            {
+                CustomViewportScaleOptions = JsonSerializer.Deserialize<List<ViewportScaleOption>>(data);
+            }
+        }
+
+        /// <summary>
+        /// Saves the custom viewport scaling options.
+        /// </summary>
+        public void SaveCustomViewportScalingOptions()
+        {
+            var customOptions = JsonSerializer.Serialize(CustomViewportScaleOptions);
+            Editor.Instance.ProjectCache.SetCustomData("CustomViewportScalingOptions",  customOptions);
         }
 
         /// <inheritdoc />
@@ -410,23 +540,6 @@ namespace FlaxEditor.Modules
             }
         }
 
-        private class CustomWindowBorderControl : Control
-        {
-            /// <inheritdoc />
-            public override void Draw()
-            {
-                var win = RootWindow.Window;
-                if (win.IsMaximized)
-                    return;
-
-                var color = Editor.Instance.UI.StatusBar.StatusColor;
-                var rect = new Rectangle(0.5f, 0.5f, Parent.Width - 1.0f, Parent.Height - 1.0f - StatusBar.DefaultHeight);
-                Render2D.DrawLine(rect.UpperLeft, rect.UpperRight, color);
-                Render2D.DrawLine(rect.UpperLeft, rect.BottomLeft, color);
-                Render2D.DrawLine(rect.UpperRight, rect.BottomRight, color);
-            }
-        }
-
         /// <inheritdoc />
         public override void OnEndInit()
         {
@@ -458,13 +571,6 @@ namespace FlaxEditor.Modules
             UpdateToolstrip();
         }
 
-        /// <inheritdoc />
-        public override void OnExit()
-        {
-            // Cleanup dock panel hint proxy windows (Flax will destroy them by var but it's better to clear them earlier)
-            DockHintWindow.Proxy.Dispose();
-        }
-
         private IColorPickerDialog ShowPickColorDialog(Control targetControl, Color initialValue, ColorValueBox.ColorPickerEvent colorChanged, ColorValueBox.ColorPickerClosedEvent pickerClosed, bool useDynamicEditing)
         {
             var dialog = new ColorPickerDialog(initialValue, colorChanged, pickerClosed, useDynamicEditing);
@@ -518,10 +624,12 @@ namespace FlaxEditor.Modules
 
         private void InitMainMenu(RootControl mainWindow)
         {
-            MainMenu = new MainMenu(mainWindow)
+            MainMenu = new MainMenu()
             {
                 Parent = mainWindow
             };
+            if (Utilities.Utils.UseCustomWindowDecorations(isMainWindow: true))
+                MainMenu.Height = 28;
 
             var inputOptions = Editor.Options.Options.Input;
 
@@ -538,6 +646,7 @@ namespace FlaxEditor.Modules
             _menuFileGenerateScriptsProjectFiles = cm.AddButton("Generate scripts project files", inputOptions.GenerateScriptsProject, Editor.ProgressReporting.GenerateScriptsProjectFiles.RunAsync);
             _menuFileRecompileScripts = cm.AddButton("Recompile scripts", inputOptions.RecompileScripts, ScriptsBuilder.Compile);
             cm.AddSeparator();
+            cm.AddButton("New project", NewProject);
             cm.AddButton("Open project...", OpenProject);
             cm.AddButton("Reload project", ReloadProject);
             cm.AddButton("Open project folder", () => FileSystem.ShowFileExplorer(Editor.Instance.GameProject.ProjectFolderPath));
@@ -568,7 +677,7 @@ namespace FlaxEditor.Modules
                 if (item != null)
                     Editor.ContentEditing.Open(item);
             });
-            cm.AddButton("Editor Options", () => Editor.Windows.EditorOptionsWin.Show());
+            cm.AddButton("Editor Options", inputOptions.EditorOptionsWindow, () => Editor.Windows.EditorOptionsWin.Show());
 
             // Scene
             MenuScene = MainMenu.AddButton("Scene");
@@ -661,6 +770,20 @@ namespace FlaxEditor.Modules
             cm.AddButton("Information about Flax", () => new AboutDialog().Show());
         }
 
+        private void InitWindowDecorations(RootControl mainWindow)
+        {
+            ScriptsBuilder.GetBinariesConfiguration(out _, out _, out _, out var configuration);
+            var driver = Platform.DisplayServer;
+            if (!string.IsNullOrEmpty(driver))
+                driver = $" ({driver})";
+            
+            WindowDecorations = new MainWindowDecorations(mainWindow, !Utilities.Utils.UseCustomWindowDecorations(isMainWindow: true))
+            {
+                Parent = mainWindow,
+                IconTooltipText = $"{mainWindow.RootWindow.Title}\nVersion {Globals.EngineVersion}\nConfiguration {configuration}\nGraphics {GPUDevice.Instance.RendererType}{driver}",
+            };
+        }
+        
         private void OnOptionsChanged(EditorOptions options)
         {
             var inputOptions = options.Input;
@@ -829,6 +952,17 @@ namespace FlaxEditor.Modules
             MasterPanel.Offsets = new Margin(0, 0, ToolStrip.Bottom, StatusBar.Height);
         }
 
+        private void NewProject()
+        {
+            // Ask user to create project file
+            if (FileSystem.ShowSaveFileDialog(Editor.Windows.MainWindow, null, "Project files (*.flaxproj)\0*.flaxproj\0All files (*.*)\0*.*\0", false, "Create project file", out var files))
+                return;
+            if (files != null && files.Length > 0)
+            {
+                Editor.NewProject(files[0]);
+            }
+        }
+
         private void OpenProject()
         {
             // Ask user to select project file
@@ -1070,6 +1204,7 @@ namespace FlaxEditor.Modules
         {
             // Clear UI references (GUI cannot be used after window closing)
             MainMenu = null;
+            WindowDecorations = null;
             ToolStrip = null;
             MasterPanel = null;
             StatusBar = null;
@@ -1085,5 +1220,267 @@ namespace FlaxEditor.Modules
             MenuTools = null;
             MenuHelp = null;
         }
+
+        internal void CreateViewportSizingContextMenu(ContextMenu vsMenu, int defaultScaleActiveIndex, int customScaleActiveIndex, bool prefabViewport, Action<ViewportScaleOption> changeView, Action<int, int> changeActiveIndices)
+        {
+            // Add default viewport sizing options
+            var defaultOptions = DefaultViewportScaleOptions;
+            for (int i = 0; i < defaultOptions.Count; i++)
+            {
+                var viewportScale = defaultOptions[i];
+                if (prefabViewport && viewportScale.ScaleType == ViewportScaleOption.ViewportScaleType.Aspect)
+                    continue; // Skip aspect ratio types in prefab
+                var button = vsMenu.AddButton(viewportScale.Label);
+                button.CloseMenuOnClick = false;
+                button.Tag = viewportScale;
+
+                // No default index is active
+                if (defaultScaleActiveIndex == -1)
+                {
+                    button.Icon = SpriteHandle.Invalid;
+                }
+                // This is the active index
+                else if (defaultScaleActiveIndex == i)
+                {
+                    button.Icon = Style.Current.CheckBoxTick;
+                    changeView(viewportScale);
+                }
+
+                button.Clicked += () =>
+                {
+                    if (button.Tag == null)
+                        return;
+
+                    // Reset selected icon on all buttons
+                    foreach (var child in vsMenu.Items)
+                    {
+                        if (child is ContextMenuButton cmb && cmb.Tag is UIModule.ViewportScaleOption v)
+                        {
+                            if (cmb == button)
+                            {
+                                button.Icon = Style.Current.CheckBoxTick;
+                                var index = defaultOptions.FindIndex(x => x == v);
+                                changeActiveIndices(index, -1); // Reset custom index because default was chosen
+                                changeView(v);
+                            }
+                            else if (cmb.Icon != SpriteHandle.Invalid)
+                            {
+                                cmb.Icon = SpriteHandle.Invalid;
+                            }
+                        }
+                    }
+                };
+            }
+            if (defaultOptions.Count != 0)
+                vsMenu.AddSeparator();
+
+            // Add custom viewport options
+            var customOptions = CustomViewportScaleOptions;
+            for (int i = 0; i < customOptions.Count; i++)
+            {
+                var viewportScale = customOptions[i];
+                if (prefabViewport && viewportScale.ScaleType == ViewportScaleOption.ViewportScaleType.Aspect)
+                    continue; // Skip aspect ratio types in prefab
+                var childCM = vsMenu.AddChildMenu(viewportScale.Label);
+                childCM.CloseMenuOnClick = false;
+                childCM.Tag = viewportScale;
+
+                // No custom index is active
+                if (customScaleActiveIndex == -1)
+                {
+                    childCM.Icon = SpriteHandle.Invalid;
+                }
+                // This is the active index
+                else if (customScaleActiveIndex == i)
+                {
+                    childCM.Icon = Style.Current.CheckBoxTick;
+                    changeView(viewportScale);
+                }
+
+                var applyButton = childCM.ContextMenu.AddButton("Apply");
+                applyButton.Tag = childCM.Tag = viewportScale;
+                applyButton.CloseMenuOnClick = false;
+                applyButton.Clicked += () =>
+                {
+                    if (childCM.Tag == null)
+                        return;
+
+                    // Reset selected icon on all buttons
+                    foreach (var child in vsMenu.Items)
+                    {
+                        if (child is ContextMenuButton cmb && cmb.Tag is UIModule.ViewportScaleOption v)
+                        {
+                            if (child == childCM)
+                            {
+                                childCM.Icon = Style.Current.CheckBoxTick;
+                                var index = customOptions.FindIndex(x => x == v);
+                                changeActiveIndices(-1, index); // Reset default index because custom was chosen
+                                changeView(v);
+                            }
+                            else if (cmb.Icon != SpriteHandle.Invalid)
+                            {
+                                cmb.Icon = SpriteHandle.Invalid;
+                            }
+                        }
+                    }
+                };
+
+                var deleteButton = childCM.ContextMenu.AddButton("Delete");
+                deleteButton.CloseMenuOnClick = false;
+                deleteButton.Clicked += () =>
+                {
+                    if (childCM.Tag == null)
+                        return;
+
+                    var v = (ViewportScaleOption)childCM.Tag;
+                    if (childCM.Icon != SpriteHandle.Invalid)
+                    {
+                        changeActiveIndices(-1, 0);
+                        changeView(defaultOptions[0]);
+                    }
+                    customOptions.Remove(v);
+                    SaveCustomViewportScalingOptions();
+                    vsMenu.DisposeAllItems();
+                    CreateViewportSizingContextMenu(vsMenu, defaultScaleActiveIndex, customScaleActiveIndex, prefabViewport, changeView, changeActiveIndices);
+                    vsMenu.PerformLayout();
+                };
+            }
+            if (customOptions.Count != 0)
+                vsMenu.AddSeparator();
+
+            // Add button
+            var add = vsMenu.AddButton("Add...");
+            add.CloseMenuOnClick = false;
+            add.Clicked += () =>
+            {
+                var popup = new ContextMenuBase
+                {
+                    Size = new Float2(230, 125),
+                    ClipChildren = false,
+                    CullChildren = false,
+                };
+                popup.Show(add, new Float2(add.Width, 0));
+
+                var nameLabel = new Label
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    Text = "Name",
+                    HorizontalAlignment = TextAlignment.Near,
+                };
+                nameLabel.LocalX += 10;
+                nameLabel.LocalY += 10;
+
+                var nameTextBox = new TextBox
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    IsMultiline = false,
+                };
+                nameTextBox.LocalX += 100;
+                nameTextBox.LocalY += 10;
+
+                var typeLabel = new Label
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    Text = "Type",
+                    HorizontalAlignment = TextAlignment.Near,
+                };
+                typeLabel.LocalX += 10;
+                typeLabel.LocalY += 35;
+
+                var typeDropdown = new Dropdown
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    Items = { "Aspect", "Resolution" },
+                    SelectedItem = "Aspect",
+                    Visible = !prefabViewport,
+                    Width = nameTextBox.Width
+                };
+                typeDropdown.LocalY += 35;
+                typeDropdown.LocalX += 100;
+
+                var whLabel = new Label
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    Text = "Width & Height",
+                    HorizontalAlignment = TextAlignment.Near,
+                };
+                whLabel.LocalX += 10;
+                whLabel.LocalY += 60;
+
+                var wValue = new IntValueBox(16)
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    MinValue = 1,
+                    Width = 55,
+                };
+                wValue.LocalY += 60;
+                wValue.LocalX += 100;
+
+                var hValue = new IntValueBox(9)
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    MinValue = 1,
+                    Width = 55,
+                };
+                hValue.LocalY += 60;
+                hValue.LocalX += 165;
+
+                var submitButton = new Button
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    Text = "Submit",
+                    Width = 70,
+                };
+                submitButton.LocalX += 40;
+                submitButton.LocalY += 90;
+                submitButton.Clicked += () =>
+                {
+                    Enum.TryParse(typeDropdown.SelectedItem, out ViewportScaleOption.ViewportScaleType type);
+                    if (prefabViewport)
+                        type = ViewportScaleOption.ViewportScaleType.Resolution;
+
+                    var combineString = type == ViewportScaleOption.ViewportScaleType.Aspect ? ":" : "x";
+                    var name = nameTextBox.Text + " (" + wValue.Value + combineString + hValue.Value + ") " + typeDropdown.SelectedItem;
+                    var newViewportOption = new ViewportScaleOption
+                    {
+                        ScaleType = type,
+                        Label = name,
+                        Size = new Int2(wValue.Value, hValue.Value),
+                    };
+
+                    customOptions.Add(newViewportOption);
+                    SaveCustomViewportScalingOptions();
+                    vsMenu.DisposeAllItems();
+                    CreateViewportSizingContextMenu(vsMenu, defaultScaleActiveIndex, customScaleActiveIndex, prefabViewport, changeView, changeActiveIndices);
+                    vsMenu.PerformLayout();
+                };
+
+                var cancelButton = new Button
+                {
+                    Parent = popup,
+                    AnchorPreset = AnchorPresets.TopLeft,
+                    Text = "Cancel",
+                    Width = 70,
+                };
+                cancelButton.LocalX += 120;
+                cancelButton.LocalY += 90;
+                cancelButton.Clicked += () =>
+                {
+                    nameTextBox.Clear();
+                    typeDropdown.SelectedItem = "Aspect";
+                    hValue.Value = 9;
+                    wValue.Value = 16;
+                    popup.Hide();
+                };
+            };
+        }
     }
 }

Source/Editor/Modules/WindowsModule.cs

@@ -10,7 +10,6 @@ using System.Text;
 using System.Xml;
 using FlaxEditor.Content;
 using FlaxEditor.GUI.Dialogs;
-using FlaxEditor.GUI.Docking;
 using FlaxEditor.Windows;
 using FlaxEditor.Windows.Assets;
 using FlaxEditor.Windows.Profiler;
@@ -758,17 +757,19 @@ namespace FlaxEditor.Modules
             var settings = CreateWindowSettings.Default;
             settings.Title = "Flax Editor";
             settings.Size = Platform.DesktopSize * 0.75f;
+            settings.MinimumSize = new Float2(200, 150);
             settings.StartPosition = WindowStartPosition.CenterScreen;
             settings.ShowAfterFirstPaint = true;
-#if PLATFORM_WINDOWS
-            if (!Editor.Instance.Options.Options.Interface.UseNativeWindowSystem)
+            
+            if (Utilities.Utils.UseCustomWindowDecorations(isMainWindow: true))
             {
                 settings.HasBorder = false;
-
+#if PLATFORM_WINDOWS && !PLATFORM_SDL
                 // Skip OS sizing frame and implement it using LeftButtonHit
                 settings.HasSizingFrame = false;
+#endif
             }
-#elif PLATFORM_LINUX
+#if PLATFORM_LINUX && !PLATFORM_SDL
             settings.HasBorder = false;
 #endif
             MainWindow = Platform.CreateWindow(ref settings);

Source/Editor/Options/InputOptions.cs

@@ -650,45 +650,53 @@ namespace FlaxEditor.Options
         [EditorDisplay("Windows"), EditorOrder(4020)]
         public InputBinding VisualScriptDebuggerWindow = new InputBinding(KeyboardKeys.None);
 
+        [DefaultValue(typeof(InputBinding), "Control+Comma")]
+        [EditorDisplay("Windows"), EditorOrder(4030)]
+        public InputBinding EditorOptionsWindow = new InputBinding(KeyboardKeys.Comma, KeyboardKeys.Control);
+
         #endregion
 
-        #region Node editors
+        #region Node Editors
 
         [DefaultValue(typeof(InputBinding), "Shift+W")]
-        [EditorDisplay("Node editors"), EditorOrder(4500)]
+        [EditorDisplay("Node Editors"), EditorOrder(4500)]
         public InputBinding NodesAlignTop = new InputBinding(KeyboardKeys.W, KeyboardKeys.Shift);
 
         [DefaultValue(typeof(InputBinding), "Shift+A")]
-        [EditorDisplay("Node editors"), EditorOrder(4510)]
+        [EditorDisplay("Node Editors"), EditorOrder(4510)]
         public InputBinding NodesAlignLeft = new InputBinding(KeyboardKeys.A, KeyboardKeys.Shift);
 
         [DefaultValue(typeof(InputBinding), "Shift+S")]
-        [EditorDisplay("Node editors"), EditorOrder(4520)]
+        [EditorDisplay("Node Editors"), EditorOrder(4520)]
         public InputBinding NodesAlignBottom = new InputBinding(KeyboardKeys.S, KeyboardKeys.Shift);
 
         [DefaultValue(typeof(InputBinding), "Shift+D")]
-        [EditorDisplay("Node editors"), EditorOrder(4530)]
+        [EditorDisplay("Node Editors"), EditorOrder(4530)]
         public InputBinding NodesAlignRight = new InputBinding(KeyboardKeys.D, KeyboardKeys.Shift);
 
         [DefaultValue(typeof(InputBinding), "Alt+Shift+W")]
-        [EditorDisplay("Node editors"), EditorOrder(4540)]
+        [EditorDisplay("Node Editors"), EditorOrder(4540)]
         public InputBinding NodesAlignMiddle = new InputBinding(KeyboardKeys.W, KeyboardKeys.Shift, KeyboardKeys.Alt);
 
         [DefaultValue(typeof(InputBinding), "Alt+Shift+S")]
-        [EditorDisplay("Node editors"), EditorOrder(4550)]
+        [EditorDisplay("Node Editors"), EditorOrder(4550)]
         public InputBinding NodesAlignCenter = new InputBinding(KeyboardKeys.S, KeyboardKeys.Shift, KeyboardKeys.Alt);
 
         [DefaultValue(typeof(InputBinding), "Q")]
-        [EditorDisplay("Node editors"), EditorOrder(4560)]
+        [EditorDisplay("Node Editors"), EditorOrder(4560)]
         public InputBinding NodesAutoFormat = new InputBinding(KeyboardKeys.Q);
 
-        [DefaultValue(typeof(InputBinding), "None")]
-        [EditorDisplay("Node editors"), EditorOrder(4570)]
-        public InputBinding NodesDistributeHorizontal = new InputBinding(KeyboardKeys.None);
+        [DefaultValue(typeof(InputBinding), "Shift+Q")]
+        [EditorDisplay("Node Editors"), EditorOrder(4560)]
+        public InputBinding NodesStraightenConnections = new InputBinding(KeyboardKeys.Q, KeyboardKeys.Shift);
 
-        [DefaultValue(typeof(InputBinding), "None")]
-        [EditorDisplay("Node editors"), EditorOrder(4580)]
-        public InputBinding NodesDistributeVertical = new InputBinding(KeyboardKeys.None);
+        [DefaultValue(typeof(InputBinding), "Alt+W")]
+        [EditorDisplay("Node Editors"), EditorOrder(4570)]
+        public InputBinding NodesDistributeHorizontal = new InputBinding(KeyboardKeys.W, KeyboardKeys.Alt);
+
+        [DefaultValue(typeof(InputBinding), "Alt+A")]
+        [EditorDisplay("Node Editors"), EditorOrder(4580)]
+        public InputBinding NodesDistributeVertical = new InputBinding(KeyboardKeys.A, KeyboardKeys.Alt);
 
         #endregion
     }