Merge branch 'unload_alc_fix' of https://github.com/GoaLitiuM/FlaxEngine into GoaLitiuM-unload_alc_fix

Source/Editor/CustomEditors/CustomEditorPresenter.cs

@@ -196,6 +196,15 @@ namespace FlaxEditor.CustomEditors
                 Presenter.AfterLayout?.Invoke(layout);
             }
 
+            /// <inheritdoc />
+            protected override void Deinitialize()
+            {
+                Editor = null;
+                _overrideEditor = null;
+
+                base.Deinitialize();
+            }
+
             /// <inheritdoc />
             protected override void OnModified()
             {

Source/Editor/CustomEditors/Dedicated/ActorEditor.cs

@@ -205,7 +205,7 @@ namespace FlaxEditor.CustomEditors.Dedicated
             if (_linkedPrefabId != Guid.Empty)
             {
                 _linkedPrefabId = Guid.Empty;
-                Editor.Instance.Prefabs.PrefabApplied -= OnPrefabApplying;
+                Editor.Instance.Prefabs.PrefabApplying -= OnPrefabApplying;
                 Editor.Instance.Prefabs.PrefabApplied -= OnPrefabApplied;
             }
         }

Source/Editor/CustomEditors/Dedicated/ScriptsEditor.cs

@@ -1057,6 +1057,7 @@ namespace FlaxEditor.CustomEditors.Dedicated
         protected override void Deinitialize()
         {
             _scriptToggles = null;
+            _scripts.Clear();
 
             base.Deinitialize();
         }

Source/Editor/CustomEditors/Editors/GenericEditor.cs

@@ -819,6 +819,15 @@ namespace FlaxEditor.CustomEditors.Editors
             OnGroupsEnd();
         }
 
+        /// <inheritdoc />
+        protected override void Deinitialize()
+        {
+            _visibleIfCaches = null;
+            _visibleIfPropertiesListsCache = null;
+
+            base.Deinitialize();
+        }
+
         /// <inheritdoc />
         public override void Refresh()
         {

Source/Editor/GUI/Docking/DockWindow.cs

@@ -464,7 +464,7 @@ namespace FlaxEditor.GUI.Docking
         {
             base.Focus();
 
-            SelectTab();
+            SelectTab(false);
             BringToFront();
         }
 

Source/Editor/Modules/ContentDatabaseModule.cs

@@ -21,6 +21,7 @@ namespace FlaxEditor.Modules
         private bool _enableEvents;
         private bool _isDuringFastSetup;
         private bool _rebuildFlag;
+        private bool _rebuildInitFlag;
         private int _itemsCreated;
         private int _itemsDeleted;
         private readonly HashSet<MainContentTreeNode> _dirtyNodes = new HashSet<MainContentTreeNode>();
@@ -61,7 +62,7 @@ namespace FlaxEditor.Modules
         public event Action WorkspaceModified;
 
         /// <summary>
-        /// Occurs when workspace has will be rebuilt.
+        /// Occurs when workspace will be rebuilt.
         /// </summary>
         public event Action WorkspaceRebuilding;
 
@@ -88,6 +89,9 @@ namespace FlaxEditor.Modules
 
             // Register AssetItems serialization helper (serialize ref ID only)
             FlaxEngine.Json.JsonSerializer.Settings.Converters.Add(new AssetItemConverter());
+
+            ScriptsBuilder.ScriptsReload += OnScriptsReload;
+            ScriptsBuilder.ScriptsReloadEnd += OnScriptsReloadEnd;
         }
 
         private void OnContentAssetDisposing(Asset asset)
@@ -817,6 +821,7 @@ namespace FlaxEditor.Modules
             Profiler.BeginEvent("ContentDatabase.Rebuild");
             var startTime = Platform.TimeSeconds;
             _rebuildFlag = false;
+            _rebuildInitFlag = false;
             _enableEvents = false;
 
             // Load all folders
@@ -1230,8 +1235,6 @@ namespace FlaxEditor.Modules
                 LoadProjects(Game.Project);
             }
 
-            RebuildInternal();
-
             Editor.ContentImporting.ImportFileEnd += (obj, failed) =>
             {
                 var path = obj.ResultUrl;
@@ -1239,6 +1242,15 @@ namespace FlaxEditor.Modules
                     FlaxEngine.Scripting.InvokeOnUpdate(() => OnImportFileDone(path));
             };
             _enableEvents = true;
+            _rebuildInitFlag = true;
+        }
+
+        /// <inheritdoc />
+        public override void OnEndInit()
+        {
+            // Handle init when project was loaded without scripts loading ()
+            if (_rebuildInitFlag)
+                RebuildInternal();
         }
 
         private void OnImportFileDone(string path)
@@ -1313,6 +1325,52 @@ namespace FlaxEditor.Modules
             }
         }
 
+        private void OnScriptsReload()
+        {
+            var enabledEvents = _enableEvents;
+            _enableEvents = false;
+            _isDuringFastSetup = true;
+            var startItems = _itemsCreated;
+            foreach (var project in Projects)
+            {
+                if (project.Content != null)
+                {
+                    //Dispose(project.Content.Folder);
+                    for (int i = 0; i < project.Content.Folder.Children.Count; i++)
+                    {
+                        Dispose(project.Content.Folder.Children[i]);
+                        i--;
+                    }
+                }
+                if (project.Source != null)
+                {
+                    //Dispose(project.Source.Folder);
+                    for (int i = 0; i < project.Source.Folder.Children.Count; i++)
+                    {
+                        Dispose(project.Source.Folder.Children[i]);
+                        i--;
+                    }
+                }
+            }
+
+            List<ContentProxy> removeProxies = new List<ContentProxy>();
+            foreach (var proxy in Editor.Instance.ContentDatabase.Proxy)
+            {
+                if (proxy.GetType().IsCollectible)
+                    removeProxies.Add(proxy);
+            }
+            foreach (var proxy in removeProxies)
+                RemoveProxy(proxy, false);
+
+            _isDuringFastSetup = false;
+            _enableEvents = enabledEvents;
+        }
+
+        private void OnScriptsReloadEnd()
+        {
+            RebuildInternal();
+        }
+
         /// <inheritdoc />
         public override void OnUpdate()
         {
@@ -1340,6 +1398,8 @@ namespace FlaxEditor.Modules
         public override void OnExit()
         {
             FlaxEngine.Content.AssetDisposing -= OnContentAssetDisposing;
+            ScriptsBuilder.ScriptsReload -= OnScriptsReload;
+            ScriptsBuilder.ScriptsReloadEnd -= OnScriptsReloadEnd;
 
             // Disable events
             _enableEvents = false;

Source/Editor/Modules/ContentImportingModule.cs

@@ -391,6 +391,20 @@ namespace FlaxEditor.Modules
         public override void OnInit()
         {
             ImportFileEntry.RegisterDefaultTypes();
+            ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
+        }
+
+        private void OnScriptsReloadBegin()
+        {
+            // Remove import file types from scripting assemblies
+            List<string> removeFileTypes = new List<string>();
+            foreach (var pair in ImportFileEntry.FileTypes)
+            {
+                if (pair.Value.Method.IsCollectible || (pair.Value.Target != null && pair.Value.Target.GetType().IsCollectible))
+                    removeFileTypes.Add(pair.Key);
+            }
+            foreach (var fileType in removeFileTypes)
+                ImportFileEntry.FileTypes.Remove(fileType);
         }
 
         /// <inheritdoc />
@@ -451,6 +465,7 @@ namespace FlaxEditor.Modules
         /// <inheritdoc />
         public override void OnExit()
         {
+            ScriptsBuilder.ScriptsReloadBegin -= OnScriptsReloadBegin;
             EndWorker();
         }
     }

Source/Editor/Modules/SceneModule.cs

@@ -58,7 +58,7 @@ namespace FlaxEditor.Modules
         : base(editor)
         {
             // After editor cache but before the windows
-            InitOrder = -900;
+            InitOrder = -800;
         }
 
         /// <summary>

Source/Editor/Modules/UIModule.cs

@@ -160,7 +160,7 @@ namespace FlaxEditor.Modules
         internal UIModule(Editor editor)
         : base(editor)
         {
-            InitOrder = -90;
+            InitOrder = -70;
             VisjectSurfaceBackground = FlaxEngine.Content.LoadAsyncInternal<Texture>("Editor/VisjectSurface");
             ColorValueBox.ShowPickColorDialog += ShowPickColorDialog;
         }

Source/Editor/Modules/WindowsModule.cs

@@ -5,10 +5,12 @@ using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
 using System.Reflection;
+using System.Runtime.InteropServices;
 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;
@@ -39,6 +41,7 @@ namespace FlaxEditor.Modules
             
             public DockState DockState;
             public DockPanel DockedTo;
+            public int DockedTabIndex;
             public float? SplitterValue = null;
 
             public bool SelectOnShow = false;
@@ -48,6 +51,8 @@ namespace FlaxEditor.Modules
             public Float2 FloatSize;
             public Float2 FloatPosition;
 
+            public Guid AssetItemID;
+
             // Constructor, to allow for default values
             public WindowRestoreData()
             {
@@ -803,43 +808,64 @@ namespace FlaxEditor.Modules
             Level.SceneSaving += OnSceneSaving;
             Level.SceneUnloaded += OnSceneUnloaded;
             Level.SceneUnloading += OnSceneUnloading;
-            ScriptsBuilder.ScriptsReloadEnd += OnScriptsReloadEnd;
+            Editor.ContentDatabase.WorkspaceRebuilt += OnWorkspaceRebuilt;
             Editor.StateMachine.StateChanged += OnEditorStateChanged;
         }
 
+        internal void AddToRestore(AssetEditorWindow win)
+        {
+            AddToRestore(win, win.GetType(), new WindowRestoreData
+            {
+                AssetItemID = win.Item.ID,
+            });
+        }
+
         internal void AddToRestore(CustomEditorWindow win)
         {
-            var type = win.GetType();
+            AddToRestore(win.Window, win.GetType(), new WindowRestoreData());
+        }
 
+        private void AddToRestore(EditorWindow win, Type type, WindowRestoreData winData)
+        {
             // Validate if can restore type
             var constructor = type.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null);
             if (constructor == null || type.IsGenericType)
                 return;
 
-            var winData = new WindowRestoreData();
+            var panel = win.ParentDockPanel;
-            var panel = win.Window.ParentDockPanel;
 
             // Ensure that this window is only selected following recompilation
             // if it was the active tab in its dock panel. Otherwise, there is a
             // risk of interrupting the user's workflow by potentially selecting
             // background tabs.
-            winData.SelectOnShow = panel.SelectedTab == win.Window;
+            var window = win.RootWindow.Window;
-            if (panel is FloatWindowDockPanel)
+            winData.SelectOnShow = panel.SelectedTab == win;
+            winData.DockedTabIndex = 0;
+            if (panel is FloatWindowDockPanel && window != null && panel.TabsCount == 1)
             {
                 winData.DockState = DockState.Float;
-                var window = win.Window.RootWindow.Window;
                 winData.FloatPosition = window.Position;
                 winData.FloatSize = window.ClientSize;
                 winData.Maximize = window.IsMaximized;
                 winData.Minimize = window.IsMinimized;
+                winData.DockedTo = panel;
             }
             else
             {
+                for (int i = 0; i < panel.Tabs.Count; i++)
+                {
+                    if (panel.Tabs[i] == win)
+                    {
+                        winData.DockedTabIndex = i;
+                        break;
+                    }
+                }
                 if (panel.TabsCount > 1)
                 {
                     winData.DockState = DockState.DockFill;
                     winData.DockedTo = panel;
-                }else
+                }
+                else
                 {
                     winData.DockState = panel.TryGetDockState(out var splitterValue);
                     winData.DockedTo = panel.ParentDockPanel;
@@ -851,38 +877,93 @@ namespace FlaxEditor.Modules
             _restoreWindows.Add(winData);
         }
 
-        private void OnScriptsReloadEnd()
+        private void OnWorkspaceRebuilt()
         {
-            for (int i = 0; i < _restoreWindows.Count; i++)
+            // Go in reverse order to create floating Prefab windows first before docked windows
+            for (int i = _restoreWindows.Count - 1; i >= 0; i--)
             {
                 var winData = _restoreWindows[i];
 
                 try
                 {
                     var assembly = Utils.GetAssemblyByName(winData.AssemblyName);
-                    if (assembly != null)
+                    if (assembly == null)
+                        continue;
+                    
+                    var type = assembly.GetType(winData.TypeName);
+                    if (type == null)
+                        continue;
+
+                    if (type.IsAssignableTo(typeof(AssetEditorWindow)))
                     {
-                        var type = assembly.GetType(winData.TypeName);
+                        var ctor = type.GetConstructor(new Type[] { typeof(Editor), typeof(AssetItem) });
-                        if (type != null)
+                        var assetItem = Editor.ContentDatabase.FindAsset(winData.AssetItemID);
+                        var win = (AssetEditorWindow)ctor.Invoke(new object[] { Editor.Instance, assetItem });
+                        win.Show(winData.DockState, winData.DockState != DockState.Float ? winData.DockedTo : null, winData.SelectOnShow, winData.SplitterValue);
+                        if (winData.DockState == DockState.Float)
                         {
-                            var win = (CustomEditorWindow)Activator.CreateInstance(type);
+                            var window = win.RootWindow.Window;
-                            win.Show(winData.DockState, winData.DockedTo, winData.SelectOnShow, winData.SplitterValue);
+                            window.Position = winData.FloatPosition;
-                            if (winData.DockState == DockState.Float)
+                            if (winData.Maximize)
                             {
-                                var window = win.Window.RootWindow.Window;
+                                window.Maximize();
-                                window.Position = winData.FloatPosition;
+                            }
-                                if (winData.Maximize)
+                            else if (winData.Minimize)
-                                {
+                            {
-                                    window.Maximize();
+                                window.Minimize();
-                                }
+                            }
-                                else if (winData.Minimize)
+                            else
-                                {
+                            {
-                                    window.Minimize();
+                                window.ClientSize = winData.FloatSize;
-                                }
+                            }
-                                else 
+
-                                {
+                            // Update panel reference in other windows docked to this panel
-                                    window.ClientSize = winData.FloatSize;
+                            foreach (ref var otherData in CollectionsMarshal.AsSpan(_restoreWindows))
-                                }
+                            {
+                                if (otherData.DockedTo == winData.DockedTo)
+                                    otherData.DockedTo = win.ParentDockPanel;
+                            }
+                        }
+                        var panel = win.ParentDockPanel;
+                        int currentTabIndex = 0;
+                        for (int pi = 0; pi < panel.TabsCount; pi++)
+                        {
+                            if (panel.Tabs[pi] == win)
+                            {
+                                currentTabIndex = pi;
+                                break;
+                            }
+                        }
+                        while (currentTabIndex > winData.DockedTabIndex)
+                        {
+                            win.ParentDockPanel.MoveTabLeft(currentTabIndex);
+                            currentTabIndex--;
+                        }
+                        while (currentTabIndex < winData.DockedTabIndex)
+                        {
+                            win.ParentDockPanel.MoveTabRight(currentTabIndex);
+                            currentTabIndex++;
+                        }
+                    }
+                    else
+                    {
+                        var win = (CustomEditorWindow)Activator.CreateInstance(type);
+                        win.Show(winData.DockState, winData.DockedTo, winData.SelectOnShow, winData.SplitterValue);
+                        if (winData.DockState == DockState.Float)
+                        {
+                            var window = win.Window.RootWindow.Window;
+                            window.Position = winData.FloatPosition;
+                            if (winData.Maximize)
+                            {
+                                window.Maximize();
+                            }
+                            else if (winData.Minimize)
+                            {
+                                window.Minimize();
+                            }
+                            else
+                            {
+                                window.ClientSize = winData.FloatSize;
                             }
                         }
                     }
@@ -893,6 +974,11 @@ namespace FlaxEditor.Modules
                     Editor.LogWarning(string.Format("Failed to restore window {0} (assembly: {1})", winData.TypeName, winData.AssemblyName));
                 }
             }
+
+            // Restored windows stole the focus from Editor
+            if (_restoreWindows.Count > 0)
+                Editor.Instance.Windows.MainWindow.Focus();
+
             _restoreWindows.Clear();
         }
 
@@ -1048,7 +1134,7 @@ namespace FlaxEditor.Modules
             Level.SceneSaving -= OnSceneSaving;
             Level.SceneUnloaded -= OnSceneUnloaded;
             Level.SceneUnloading -= OnSceneUnloading;
-            ScriptsBuilder.ScriptsReloadEnd -= OnScriptsReloadEnd;
+            Editor.ContentDatabase.WorkspaceRebuilt -= OnWorkspaceRebuilt;
             Editor.StateMachine.StateChanged -= OnEditorStateChanged;
 
             // Close main window

Source/Editor/SceneGraph/SceneGraphNode.cs

@@ -469,6 +469,7 @@ namespace FlaxEditor.SceneGraph
             {
                 ChildNodes[i].OnDispose();
             }
+            ChildNodes.Clear();
 
             SceneGraphFactory.Nodes.Remove(ID);
         }

Source/Editor/Surface/AnimGraphSurface.cs

@@ -161,6 +161,8 @@ namespace FlaxEditor.Surface
 
         private void OnScriptsReloadBegin()
         {
+            _nodesCache.Clear();
+
             // Check if any of the nodes comes from the game scripts - those can be reloaded at runtime so prevent crashes
             bool hasTypeFromGameScripts = Editor.Instance.CodeEditing.AnimGraphNodes.HasTypeFromGameScripts;
 

Source/Editor/Surface/BehaviorTreeSurface.cs

@@ -24,6 +24,7 @@ namespace FlaxEditor.Surface
         public BehaviorTreeSurface(IVisjectSurfaceOwner owner, Action onSave, FlaxEditor.Undo undo)
         : base(owner, onSave, undo, CreateStyle())
         {
+            ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
         }
 
         private static SurfaceStyle CreateStyle()
@@ -35,6 +36,11 @@ namespace FlaxEditor.Surface
             return style;
         }
 
+        private void OnScriptsReloadBegin()
+        {
+            _nodesCache.Clear();
+        }
+
         private static void DrawBox(Box box)
         {
             var rect = new Rectangle(Float2.Zero, box.Size);
@@ -186,6 +192,7 @@ namespace FlaxEditor.Surface
         {
             if (IsDisposing)
                 return;
+            ScriptsBuilder.ScriptsReloadBegin -= OnScriptsReloadBegin;
             _nodesCache.Wait();
 
             base.OnDestroy();

Source/Editor/Surface/VisjectSurface.cs

@@ -415,6 +415,15 @@ namespace FlaxEditor.Surface
             // Init drag handlers
             DragHandlers.Add(_dragAssets = new DragAssets<DragDropEventArgs>(ValidateDragItem));
             DragHandlers.Add(_dragParameters = new DragNames<DragDropEventArgs>(SurfaceParameter.DragPrefix, ValidateDragParameter));
+
+            ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
+        }
+
+        private void OnScriptsReloadBegin()
+        {
+            _activeVisjectCM = null;
+            _cmPrimaryMenu?.Dispose();
+            _cmPrimaryMenu = null;
         }
 
         /// <summary>
@@ -1023,6 +1032,8 @@ namespace FlaxEditor.Surface
             _activeVisjectCM = null;
             _cmPrimaryMenu?.Dispose();
 
+            ScriptsBuilder.ScriptsReloadBegin -= OnScriptsReloadBegin;
+
             base.OnDestroy();
         }
     }

Source/Editor/Surface/VisualScriptSurface.cs

@@ -62,6 +62,12 @@ namespace FlaxEditor.Surface
         {
             _supportsImplicitCastFromObjectToBoolean = true;
             DragHandlers.Add(_dragActors = new DragActors(ValidateDragActor));
+            ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
+        }
+
+        private void OnScriptsReloadBegin()
+        {
+            _nodesCache.Clear();
         }
 
         private bool ValidateDragActor(ActorNode actor)
@@ -631,6 +637,7 @@ namespace FlaxEditor.Surface
         {
             if (IsDisposing)
                 return;
+            ScriptsBuilder.ScriptsReloadBegin -= OnScriptsReloadBegin;
             _nodesCache.Wait();
 
             base.OnDestroy();

Source/Editor/Windows/Assets/AssetEditorWindow.cs

@@ -58,6 +58,8 @@ namespace FlaxEditor.Windows.Assets
             InputActions.Add(options => options.Save, Save);
 
             UpdateTitle();
+
+            ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
         }
 
         /// <summary>
@@ -151,6 +153,8 @@ namespace FlaxEditor.Windows.Assets
         /// <inheritdoc />
         public override void OnDestroy()
         {
+            ScriptsBuilder.ScriptsReloadBegin -= OnScriptsReloadBegin;
+
             if (_item != null)
             {
                 // Ensure to remove linkage to the item
@@ -160,6 +164,15 @@ namespace FlaxEditor.Windows.Assets
             base.OnDestroy();
         }
 
+        /// <inheritdoc />
+        protected virtual void OnScriptsReloadBegin()
+        {
+            if (!IsHidden)
+            {
+                Editor.Instance.Windows.AddToRestore(this);
+            }
+        }
+
         #region IEditable Implementation
 
         private bool _isEdited;

Source/Editor/Windows/Assets/BehaviorTreeWindow.cs

@@ -268,8 +268,11 @@ namespace FlaxEditor.Windows.Assets
             UpdateKnowledge();
         }
 
-        private void OnScriptsReloadBegin()
+        /// <inheritdoc />
+        protected override void OnScriptsReloadBegin()
         {
+            base.OnScriptsReloadBegin();
+
             // TODO: impl hot-reload for BT to nicely refresh state (save asset, clear undo/properties, reload surface)
             Close();
         }

Source/Editor/Windows/Assets/JsonAssetWindow.cs

@@ -124,8 +124,10 @@ namespace FlaxEditor.Windows.Assets
             UpdateToolstrip();
         }
 
-        private void OnScriptsReloadBegin()
+        /// <inheritdoc />
+        protected override void OnScriptsReloadBegin()
         {
+            base.OnScriptsReloadBegin();
             Close();
         }
 

Source/Editor/Windows/Assets/PrefabWindow.cs

@@ -198,7 +198,6 @@ namespace FlaxEditor.Windows.Assets
 
             Editor.Prefabs.PrefabApplied += OnPrefabApplied;
             ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
-            ScriptsBuilder.ScriptsReloadEnd += OnScriptsReloadEnd;
 
             // Setup input actions
             InputActions.Add(options => options.Undo, () =>
@@ -291,8 +290,10 @@ namespace FlaxEditor.Windows.Assets
             return false;
         }
 
-        private void OnScriptsReloadBegin()
+        /// <inheritdoc />
+        protected override void OnScriptsReloadBegin()
         {
+            base.OnScriptsReloadBegin();
             _isScriptsReloading = true;
 
             if (_asset == null || !_asset.IsLoaded)
@@ -320,19 +321,8 @@ namespace FlaxEditor.Windows.Assets
             Graph.MainActor = null;
             _viewport.Prefab = null;
             _undo?.Clear(); // TODO: maybe don't clear undo?
-        }
 
-        private void OnScriptsReloadEnd()
+            Close();
-        {
-            _isScriptsReloading = false;
-
-            if (_asset == null || !_asset.IsLoaded)
-                return;
-
-            // Restore
-            OnPrefabOpened();
-            _undo.Clear();
-            ClearEditedFlag();
         }
 
         private void OnUndoEvent(IUndoAction action)
@@ -551,7 +541,6 @@ namespace FlaxEditor.Windows.Assets
         {
             Editor.Prefabs.PrefabApplied -= OnPrefabApplied;
             ScriptsBuilder.ScriptsReloadBegin -= OnScriptsReloadBegin;
-            ScriptsBuilder.ScriptsReloadEnd -= OnScriptsReloadEnd;
 
             _undo.Dispose();
             Graph.Dispose();

Source/Editor/Windows/ContentWindow.cs

@@ -29,6 +29,7 @@ namespace FlaxEditor.Windows
         private const string ProjectDataLastViewedFolder = "LastViewedFolder";
         private bool _isWorkspaceDirty;
         private string _workspaceRebuildLocation;
+        private string _lastViewedFolderBeforeReload;
         private SplitPanel _split;
         private Panel _contentViewPanel;
         private Panel _contentTreePanel;
@@ -144,26 +145,6 @@ namespace FlaxEditor.Windows
 
             FlaxEditor.Utilities.Utils.SetupCommonInputActions(this);
 
-            // Content database events
-            editor.ContentDatabase.WorkspaceModified += () => _isWorkspaceDirty = true;
-            editor.ContentDatabase.ItemRemoved += OnContentDatabaseItemRemoved;
-            editor.ContentDatabase.WorkspaceRebuilding += () => { _workspaceRebuildLocation = SelectedNode?.Path; };
-            editor.ContentDatabase.WorkspaceRebuilt += () =>
-            {
-                var selected = Editor.ContentDatabase.Find(_workspaceRebuildLocation);
-                if (selected is ContentFolder selectedFolder)
-                {
-                    _navigationUnlocked = false;
-                    RefreshView(selectedFolder.Node);
-                    _tree.Select(selectedFolder.Node);
-                    UpdateItemsSearch();
-                    _navigationUnlocked = true;
-                    UpdateUI();
-                }
-                else
-                    ShowRoot();
-            };
-
             var options = Editor.Options;
             options.OptionsChanged += OnOptionsChanged;
 
@@ -1036,6 +1017,61 @@ namespace FlaxEditor.Windows
 
         /// <inheritdoc />
         public override void OnInit()
+        {
+            // Content database events
+            Editor.ContentDatabase.WorkspaceModified += () => _isWorkspaceDirty = true;
+            Editor.ContentDatabase.ItemRemoved += OnContentDatabaseItemRemoved;
+            Editor.ContentDatabase.WorkspaceRebuilding += () => { _workspaceRebuildLocation = SelectedNode?.Path; };
+            Editor.ContentDatabase.WorkspaceRebuilt += () =>
+            {
+                var selected = Editor.ContentDatabase.Find(_workspaceRebuildLocation);
+                if (selected is ContentFolder selectedFolder)
+                {
+                    _navigationUnlocked = false;
+                    RefreshView(selectedFolder.Node);
+                    _tree.Select(selectedFolder.Node);
+                    UpdateItemsSearch();
+                    _navigationUnlocked = true;
+                    UpdateUI();
+                }
+                else if (_root != null)
+                    ShowRoot();
+            };
+
+            Refresh();
+
+            // Load last viewed folder
+            if (Editor.ProjectCache.TryGetCustomData(ProjectDataLastViewedFolder, out string lastViewedFolder))
+            {
+                if (Editor.ContentDatabase.Find(lastViewedFolder) is ContentFolder folder)
+                    _tree.Select(folder.Node);
+            }
+
+            ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
+            ScriptsBuilder.ScriptsReloadEnd += OnScriptsReloadEnd;
+        }
+
+        private void OnScriptsReloadBegin()
+        {
+            var lastViewedFolder = _tree.Selection.Count == 1 ? _tree.SelectedNode as ContentTreeNode : null;
+            _lastViewedFolderBeforeReload = lastViewedFolder?.Path ?? string.Empty;
+
+            _tree.RemoveChild(_root);
+            _root = null;
+        }
+
+        private void OnScriptsReloadEnd()
+        {
+            Refresh();
+
+            if (!string.IsNullOrEmpty(_lastViewedFolderBeforeReload))
+            {
+                if (Editor.ContentDatabase.Find(_lastViewedFolderBeforeReload) is ContentFolder folder)
+                    _tree.Select(folder.Node);
+            }
+        }
+
+        private void Refresh()
         {
             // Setup content root node
             _root = new RootContentTreeNode
@@ -1072,13 +1108,6 @@ namespace FlaxEditor.Windows
             // Update UI layout
             _isLayoutLocked = false;
             PerformLayout();
-
-            // Load last viewed folder
-            if (Editor.ProjectCache.TryGetCustomData(ProjectDataLastViewedFolder, out string lastViewedFolder))
-            {
-                if (Editor.ContentDatabase.Find(lastViewedFolder) is ContentFolder folder)
-                    _tree.Select(folder.Node);
-            }
         }
 
         /// <inheritdoc />
@@ -1226,6 +1255,8 @@ namespace FlaxEditor.Windows
             _viewDropdown = null;
 
             Editor.Options.OptionsChanged -= OnOptionsChanged;
+            ScriptsBuilder.ScriptsReloadBegin -= OnScriptsReloadBegin;
+            ScriptsBuilder.ScriptsReloadEnd -= OnScriptsReloadEnd;
 
             base.OnDestroy();
         }

Source/Editor/Windows/ToolboxWindow.cs

@@ -150,6 +150,22 @@ namespace FlaxEditor.Windows
             _searchBox.Clear();
             _groupSearch.DisposeChildren();
             _groupSearch.PerformLayout();
+
+            // Remove tabs
+            var tabs = new List<Tab>();
+            foreach (var child in _actorGroups.Children)
+            {
+                if (child is Tab tab)
+                {
+                    if (tab.Text != "Search")
+                        tabs.Add(tab);
+                }
+            }
+            foreach (var tab in tabs)
+            {
+                var group = _actorGroups.Children.Find(T => T == tab);
+                group.Dispose();
+            }
         }
 
         private void OnScriptsReloadEnd()

Source/Engine/Engine/NativeInterop.Managed.cs

@@ -176,6 +176,7 @@ namespace FlaxEngine.Interop
                 _managedHandle.Free();
                 _unmanagedData = IntPtr.Zero;
             }
+            _arrayType = _elementType = null;
             ManagedArrayPool.Put(this);
         }
 
@@ -442,22 +443,25 @@ namespace FlaxEngine.Interop
             /// <summary>
             /// Tries to free all references to old weak handles so GC can collect them.
             /// </summary>
-            internal static void TryCollectWeakHandles()
+            internal static void TryCollectWeakHandles(bool force = false)
             {
-                if (weakHandleAccumulator < nextWeakPoolCollection)
+                if (!force)
-                    return;
+                {
+                    if (weakHandleAccumulator < nextWeakPoolCollection)
+                        return;
 
-                nextWeakPoolCollection = weakHandleAccumulator + 1000;
+                    nextWeakPoolCollection = weakHandleAccumulator + 1000;
 
-                // Try to swap pools after garbage collection or whenever the pool gets too large
+                    // Try to swap pools after garbage collection or whenever the pool gets too large
-                var gc0CollectionCount = GC.CollectionCount(0);
+                    var gc0CollectionCount = GC.CollectionCount(0);
-                if (gc0CollectionCount < nextWeakPoolGCCollection && weakPool.Count < WeakPoolCollectionSizeThreshold)
+                    if (gc0CollectionCount < nextWeakPoolGCCollection && weakPool.Count < WeakPoolCollectionSizeThreshold)
-                    return;
+                        return;
-                nextWeakPoolGCCollection = gc0CollectionCount + 1;
+                    nextWeakPoolGCCollection = gc0CollectionCount + 1;
 
-                // Prevent huge allocations from swapping the pools in the middle of the operation
+                    // Prevent huge allocations from swapping the pools in the middle of the operation
-                if (System.Diagnostics.Stopwatch.GetElapsedTime(lastWeakPoolCollectionTime).TotalMilliseconds < WeakPoolCollectionTimeThreshold)
+                    if (System.Diagnostics.Stopwatch.GetElapsedTime(lastWeakPoolCollectionTime).TotalMilliseconds < WeakPoolCollectionTimeThreshold)
-                    return;
+                        return;
+                }
                 lastWeakPoolCollectionTime = System.Diagnostics.Stopwatch.GetTimestamp();
 
                 // Swap the pools and release the oldest pool for GC

Source/Engine/Engine/NativeInterop.Unmanaged.cs

@@ -1054,7 +1054,49 @@ namespace FlaxEngine.Interop
         }
 
         [UnmanagedCallersOnly]
-        internal static void ReloadScriptingAssemblyLoadContext()
+        internal static void CreateScriptingAssemblyLoadContext()
+        {
+#if FLAX_EDITOR
+            if (scriptingAssemblyLoadContext != null)
+            {
+                // Wait for previous ALC to finish unloading, track it without holding strong references to it
+                GCHandle weakRef = GCHandle.Alloc(scriptingAssemblyLoadContext, GCHandleType.WeakTrackResurrection);
+                scriptingAssemblyLoadContext = null;
+#if true
+                // In case the ALC doesn't unload properly: https://learn.microsoft.com/en-us/dotnet/standard/assembly/unloadability#debug-unloading-issues
+                while (true)
+#else
+                for (int attempts = 5; attempts > 0; attempts--)
+#endif
+                {
+                    GC.Collect();
+                    GC.WaitForPendingFinalizers();
+
+                    if (!IsHandleAlive(weakRef))
+                        break;
+                    System.Threading.Thread.Sleep(1);
+                }
+                if (IsHandleAlive(weakRef))
+                    Debug.LogWarning("Scripting AssemblyLoadContext was not unloaded.");
+                weakRef.Free();
+
+                static bool IsHandleAlive(GCHandle weakRef)
+                {
+                    // Checking the target in scope somehow holds a reference to it...?
+                    return weakRef.Target != null;
+                }
+            }
+
+            scriptingAssemblyLoadContext = new AssemblyLoadContext("Flax", isCollectible: true);
+            scriptingAssemblyLoadContext.Resolving += OnScriptingAssemblyLoadContextResolving;
+#else
+            scriptingAssemblyLoadContext = new AssemblyLoadContext("Flax", isCollectible: false);
+#endif
+            DelegateHelpers.InitMethods();
+        }
+
+        [UnmanagedCallersOnly]
+        internal static void UnloadScriptingAssemblyLoadContext()
         {
 #if FLAX_EDITOR
             // Clear all caches which might hold references to assemblies in collectible ALC
@@ -1072,24 +1114,87 @@ namespace FlaxEngine.Interop
                 handle.Free();
             propertyHandleCacheCollectible.Clear();
 
+            foreach (var key in assemblyHandles.Keys.Where(x => x.IsCollectible))
+                assemblyHandles.Remove(key);
+            foreach (var key in assemblyOwnedNativeLibraries.Keys.Where(x => x.IsCollectible))
+                assemblyOwnedNativeLibraries.Remove(key);
+
             _typeSizeCache.Clear();
 
             foreach (var pair in classAttributesCacheCollectible)
                 pair.Value.Free();
             classAttributesCacheCollectible.Clear();
 
+            ArrayFactory.marshalledTypes.Clear();
+            ArrayFactory.arrayTypes.Clear();
+            ArrayFactory.createArrayDelegates.Clear();
+
             FlaxEngine.Json.JsonSerializer.ResetCache();
+            DelegateHelpers.Release();
+
+            // Ensure both pools are empty
+            ManagedHandle.ManagedHandlePool.TryCollectWeakHandles(true);
+            ManagedHandle.ManagedHandlePool.TryCollectWeakHandles(true);
+
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
+
+            {
+                // HACK: Workaround for TypeDescriptor holding references to collectible types (https://github.com/dotnet/runtime/issues/30656)
+
+                Type TypeDescriptionProviderType = typeof(System.ComponentModel.TypeDescriptionProvider);
+                MethodInfo clearCacheMethod = TypeDescriptionProviderType?.Assembly.GetType("System.ComponentModel.ReflectionCachesUpdateHandler")?.GetMethod("ClearCache");
+                if (clearCacheMethod != null)
+                    clearCacheMethod.Invoke(null, new object[] { null });
+
+                Type TypeDescriptorType = typeof(System.ComponentModel.TypeDescriptor);
+                object s_providerTable = TypeDescriptorType?.GetField("s_providerTable", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
+
+                // Added in .NET runtime 8.0.10, used as the main locking object
+                object s_commonSyncObject = TypeDescriptorType?.GetField("s_commonSyncObject", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
+                if (s_commonSyncObject == null)
+                    s_commonSyncObject = s_providerTable;
+
+                // Removed in .NET runtime 8.0.7
+                object s_internalSyncObject = TypeDescriptorType?.GetField("s_internalSyncObject", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
+                object s_defaultProviders = TypeDescriptorType?.GetField("s_defaultProviders", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
+                if (s_internalSyncObject != null && s_defaultProviders != null)
+                {
+                    lock (s_internalSyncObject)
+                        InvokeClear(s_defaultProviders);
+                }
+
+                // Replaces s_defaultProviders in 8.0.7
+                object s_defaultProviderInitialized = TypeDescriptorType?.GetField("s_defaultProviderInitialized", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
+                if (s_commonSyncObject != null && s_defaultProviderInitialized != null)
+                {
+                    lock (s_commonSyncObject)
+                        InvokeClear(s_defaultProviderInitialized);
+                }
+
+                object s_providerTypeTable = TypeDescriptorType?.GetField("s_providerTypeTable", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)?.GetValue(null);
+                if (s_providerTable != null && s_providerTypeTable != null)
+                {
+                    lock (s_commonSyncObject)
+                        InvokeClear(s_providerTypeTable);
+                    InvokeClear(s_providerTable);
+                }
+
+                static void InvokeClear(object instance)
+                {
+                    Type type = instance.GetType();
+                    FlaxEngine.Assertions.Assert.IsTrue(type.Name == "ConcurrentDictionary`2" || type.Name == "Hashtable" || type.Name == "WeakHashtable");
+                    type.GetMethods(BindingFlags.Instance | BindingFlags.Public).FirstOrDefault(x => x.Name == "Clear")
+                        ?.Invoke(instance, new object[] { });
+                }
+            }
 
             // Unload the ALC
-            bool unloading = true;
-            scriptingAssemblyLoadContext.Unloading += (alc) => { unloading = false; };
             scriptingAssemblyLoadContext.Unload();
+            scriptingAssemblyLoadContext.Resolving -= OnScriptingAssemblyLoadContextResolving;
 
-            while (unloading)
+            GC.Collect();
-                System.Threading.Thread.Sleep(1);
+            GC.WaitForPendingFinalizers();
-
-            InitScriptingAssemblyLoadContext();
-            DelegateHelpers.InitMethods();
 #endif
         }
 

Source/Engine/Engine/NativeInterop.cs

@@ -73,19 +73,6 @@ namespace FlaxEngine.Interop
             return nativeLibrary;
         }
 
-        private static void InitScriptingAssemblyLoadContext()
-        {
-#if FLAX_EDITOR
-            var isCollectible = true;
-#else
-            var isCollectible = false;
-#endif
-            scriptingAssemblyLoadContext = new AssemblyLoadContext("Flax", isCollectible);
-#if FLAX_EDITOR
-            scriptingAssemblyLoadContext.Resolving += OnScriptingAssemblyLoadContextResolving;
-#endif
-        }
-
         [UnmanagedCallersOnly]
         internal static unsafe void Init()
         {
@@ -97,8 +84,6 @@ namespace FlaxEngine.Interop
             System.Threading.Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;
             System.Threading.Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;
 
-            InitScriptingAssemblyLoadContext();
-            DelegateHelpers.InitMethods();
         }
 
 #if FLAX_EDITOR
@@ -1475,11 +1460,11 @@ namespace FlaxEngine.Interop
 
         internal static class ArrayFactory
         {
-            private delegate Array CreateArrayDelegate(long size);
+            internal delegate Array CreateArrayDelegate(long size);
 
-            private static ConcurrentDictionary<Type, Type> marshalledTypes = new ConcurrentDictionary<Type, Type>(1, 3);
+            internal static ConcurrentDictionary<Type, Type> marshalledTypes = new ConcurrentDictionary<Type, Type>(1, 3);
-            private static ConcurrentDictionary<Type, Type> arrayTypes = new ConcurrentDictionary<Type, Type>(1, 3);
+            internal static ConcurrentDictionary<Type, Type> arrayTypes = new ConcurrentDictionary<Type, Type>(1, 3);
-            private static ConcurrentDictionary<Type, CreateArrayDelegate> createArrayDelegates = new ConcurrentDictionary<Type, CreateArrayDelegate>(1, 3);
+            internal static ConcurrentDictionary<Type, CreateArrayDelegate> createArrayDelegates = new ConcurrentDictionary<Type, CreateArrayDelegate>(1, 3);
 
             internal static Type GetMarshalledType(Type elementType)
             {
@@ -1645,17 +1630,6 @@ namespace FlaxEngine.Interop
             return RegisterType(type, true).typeHolder;
         }
 
-        internal static (TypeHolder typeHolder, ManagedHandle handle) GetTypeHolderAndManagedHandle(Type type)
-        {
-            if (managedTypes.TryGetValue(type, out (TypeHolder typeHolder, ManagedHandle handle) tuple))
-                return tuple;
-#if FLAX_EDITOR
-            if (managedTypesCollectible.TryGetValue(type, out tuple))
-                return tuple;
-#endif
-            return RegisterType(type, true);
-        }
-
         /// <summary>
         /// Returns a static ManagedHandle to TypeHolder for given Type, and caches it if needed.
         /// </summary>
@@ -1781,6 +1755,14 @@ namespace FlaxEngine.Interop
 #endif
             }
 
+            internal static void Release()
+            {
+                MakeNewCustomDelegateFunc = null;
+#if FLAX_EDITOR
+                MakeNewCustomDelegateFuncCollectible = null;
+#endif
+            }
+
             internal static Type MakeNewCustomDelegate(Type[] parameters)
             {
 #if FLAX_EDITOR

Source/Engine/Scripting/ManagedCLR/MCore.h

@@ -45,9 +45,16 @@ public:
     /// </summary>
     static void UnloadEngine();
 
+    /// <summary>
+    /// Creates the assembly load context for assemblies used by Scripting.
+    /// </summary>
+    static void CreateScriptingAssemblyLoadContext();
+
 #if USE_EDITOR
-    // Called by Scripting in a middle of hot-reload (after unloading modules but before loading them again).
+    /// <summary>
-    static void ReloadScriptingAssemblyLoadContext();
+    /// Called by Scripting in a middle of hot-reload (after unloading modules but before loading them again).
+    /// </summary>
+    static void UnloadScriptingAssemblyLoadContext();
 #endif
 
 public:

Source/Engine/Scripting/Runtime/DotNet.cpp

@@ -330,9 +330,15 @@ void MCore::UnloadEngine()
     ShutdownHostfxr();
 }
 
+void MCore::CreateScriptingAssemblyLoadContext()
+{
+    static void* CreateScriptingAssemblyLoadContextPtr = GetStaticMethodPointer(TEXT("CreateScriptingAssemblyLoadContext"));
+    CallStaticMethod<void>(CreateScriptingAssemblyLoadContextPtr);
+}
+
 #if USE_EDITOR
 
-void MCore::ReloadScriptingAssemblyLoadContext()
+void MCore::UnloadScriptingAssemblyLoadContext()
 {
     // Clear any cached class attributes (see https://github.com/FlaxEngine/FlaxEngine/issues/1108)
     for (auto e : CachedClassHandles)
@@ -377,8 +383,8 @@ void MCore::ReloadScriptingAssemblyLoadContext()
         }
     }
 
-    static void* ReloadScriptingAssemblyLoadContextPtr = GetStaticMethodPointer(TEXT("ReloadScriptingAssemblyLoadContext"));
+    static void* UnloadScriptingAssemblyLoadContextPtr = GetStaticMethodPointer(TEXT("UnloadScriptingAssemblyLoadContext"));
-    CallStaticMethod<void>(ReloadScriptingAssemblyLoadContextPtr);
+    CallStaticMethod<void>(UnloadScriptingAssemblyLoadContextPtr);
 }
 
 #endif

Source/Engine/Scripting/Runtime/Mono.cpp

@@ -715,9 +715,13 @@ void MCore::UnloadEngine()
 #endif
 }
 
+void MCore::CreateScriptingAssemblyLoadContext()
+{
+}
+
 #if USE_EDITOR
 
-void MCore::ReloadScriptingAssemblyLoadContext()
+void MCore::UnloadScriptingAssemblyLoadContext()
 {
 }
 

Source/Engine/Scripting/Runtime/None.cpp

@@ -58,9 +58,13 @@ void MCore::UnloadEngine()
     MRootDomain = nullptr;
 }
 
+void MCore::CreateScriptingAssemblyLoadContext()
+{
+}
+
 #if USE_EDITOR
 
-void MCore::ReloadScriptingAssemblyLoadContext()
+void MCore::UnloadScriptingAssemblyLoadContext()
 {
 }
 

Source/Engine/Scripting/Scripting.cpp

@@ -182,6 +182,8 @@ bool ScriptingService::Init()
         return true;
     }
 
+    MCore::CreateScriptingAssemblyLoadContext();
+
     // Cache root domain
     _rootDomain = MCore::GetRootDomain();
 
@@ -710,7 +712,8 @@ void Scripting::Reload(bool canTriggerSceneReload)
     _hasGameModulesLoaded = false;
 
     // Release and create a new assembly load context for user assemblies
-    MCore::ReloadScriptingAssemblyLoadContext();
+    MCore::UnloadScriptingAssemblyLoadContext();
+    MCore::CreateScriptingAssemblyLoadContext();
 
     // Give GC a try to cleanup old user objects and the other mess
     MCore::GC::Collect();

Source/Engine/Scripting/Scripting.cs

@@ -170,6 +170,10 @@ namespace FlaxEngine
             AppDomain.CurrentDomain.UnhandledException += OnUnhandledException;
             TaskScheduler.UnobservedTaskException += OnUnobservedTaskException;
             Localization.LocalizationChanged += OnLocalizationChanged;
+#if FLAX_EDITOR
+            FlaxEditor.ScriptsBuilder.ScriptsReloadBegin += OnScriptsReloadBegin;
+            FlaxEditor.ScriptsBuilder.ScriptsReloadEnd += OnScriptsReloadEnd;
+#endif
 
             OnLocalizationChanged();
             if (!Engine.IsEditor)
@@ -178,6 +182,19 @@ namespace FlaxEngine
             }
         }
 
+#if FLAX_EDITOR
+        private static void OnScriptsReloadBegin()
+        {
+            // Tooltip might hold references to scripting assemblies
+            Style.Current.SharedTooltip = null;
+        }
+
+        private static void OnScriptsReloadEnd()
+        {
+            Style.Current.SharedTooltip = new Tooltip();
+        }
+#endif
+
         private static void OnLocalizationChanged()
         {
             // Invariant-globalization only (see InitHostfxr with Mono)
@@ -359,6 +376,10 @@ namespace FlaxEngine
 
             MainThreadTaskScheduler.Dispose();
             Json.JsonSerializer.Dispose();
+#if FLAX_EDITOR
+            FlaxEditor.ScriptsBuilder.ScriptsReloadBegin -= OnScriptsReloadBegin;
+            FlaxEditor.ScriptsBuilder.ScriptsReloadEnd -= OnScriptsReloadEnd;
+#endif
         }
 
         /// <summary>

Source/Engine/UI/GUI/Tooltip.cs

@@ -120,6 +120,7 @@ namespace FlaxEngine.GUI
             // Unlink
             IsLayoutLocked = true;
             Parent = null;
+            _showTarget = null;
 
             // Close window
             if (_window)