_windows drag-and-drop fix

Source/Editor/GUI/Docking/DockPanelProxy.cs

@@ -170,7 +170,7 @@ 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
                 {
@@ -181,7 +181,7 @@ namespace FlaxEditor.GUI.Docking
                     _panel.SelectTab(index - 1);
 
                     // Create docking hint window
-                    DockHintWindow.Create(win, _panel.RootWindow.Window);
+                    WindowDragHelper.StartDragging(win, _panel.RootWindow.Window);
                 }
             }
         }

Source/Editor/GUI/Docking/FloatWindowDockPanel.cs

@@ -52,7 +52,7 @@ namespace FlaxEditor.GUI.Docking
                 return;
 
             // Create docking hint window
-            DockHintWindow.Create(this);
+            WindowDragHelper.StartDragging(this);
         }
 
         /// <summary>

Source/Editor/GUI/Docking/WindowDragHelper.cs

@@ -9,37 +9,36 @@ namespace FlaxEditor.GUI.Docking
     /// <summary>
     /// Helper class used to handle docking windows dragging and docking.
     /// </summary>
-    public class DockHintWindow
+    public class WindowDragHelper
     {
         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 float _lateDragStartTimer;
-        private bool _moveWindow;
         private Window _dragSourceWindow;
 
         private Rectangle _rLeft, _rRight, _rBottom, _rUpper, _rCenter;
+        private Control _dockHintDown, _dockHintUp, _dockHintLeft, _dockHintRight, _dockHintCenter;
 
-        private DockHintWindow(FloatWindowDockPanel toMove, Window dragSourceWindow)
+        /// <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;
+
+        private WindowDragHelper(FloatWindowDockPanel toMove, Window dragSourceWindow)
         {
             _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)
             {
@@ -50,50 +49,14 @@ namespace FlaxEditor.GUI.Docking
                 window.Position = Platform.MousePosition - mousePos * window.Size / previousSize;
             }
 
-            // 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
-            */
-            
-            //FlaxEngine.Input.MouseMove += OnMouseMove;
             FlaxEngine.Scripting.Update += OnUpdate;
-            _toMove.Window.Window.MouseUp += OnMouseUp;
-            /*
-            Proxy.Window.MouseUp += OnMouseUp;
-            Proxy.Window.MouseMove += OnMouseMove;
-            Proxy.Window.LostFocus += OnLostFocus;
-            _toMove.Window.Window.MouseUp += OnMouseUp; // Intercept the drag release mouse event from source window
-*/
-            // Update window GUI
-            //Proxy.Window.GUI.PerformLayout();
+            window.MouseUp += OnMouseUp;
             
             // Update rectangles
             UpdateRects();
 
-            // Enable hit window presentation
-            /*Proxy.Window.RenderingEnabled = true;
-            Proxy.Window.Show();
-            Proxy.Window.Focus();*/
-
-            // Hide base window
-            //window.Hide();
-
-            // window.Show();
             _dragSourceWindow = dragSourceWindow;
-            _moveWindow = _dragSourceWindow != null;
             if (_dragSourceWindow != null) // Detaching a tab from existing window
             {
                 _dragOffset = new Float2(window.Size.X / 2, 10.0f);
@@ -106,23 +69,12 @@ namespace FlaxEditor.GUI.Docking
             }
             else
             {
-                var mouseClientPosition = Platform.MousePosition;
-                CalculateDragOffset(mouseClientPosition);
-
                 window.DoDragDrop("", _dragOffset, window);
             }
 
+            // Ensure the dragged window stays on top of every other window
             //window.Show();
-            //window.BringToFront();
-            //window.Focus();
-            //toMove.OnShow();
-
-            // Perform layout again
-            //windowGUI.PerformLayout();
-            
-            
-            // Start tracking mouse
-            //Proxy.Window.StartTrackingMouse(false);
+            window.IsAlwaysOnTop = true;
         }
 
         /// <summary>
@@ -130,48 +82,32 @@ namespace FlaxEditor.GUI.Docking
         /// </summary>
         public void Dispose()
         {
-            // End tracking mouse
-            /*Proxy.Window.EndTrackingMouse();
-
-            // Disable rendering
-            Proxy.Window.RenderingEnabled = false;
+            var window = _toMove?.Window?.Window;
 
             // Unbind events
-            Proxy.Window.MouseUp -= OnMouseUp;
-            Proxy.Window.MouseMove -= OnMouseMove;
-            Proxy.Window.LostFocus -= OnLostFocus;
-            if (_toMove?.Window?.Window)
-                _toMove.Window.Window.MouseUp -= OnMouseUp;
-
-            // Hide the proxy
-            Proxy.Hide();*/
+            FlaxEngine.Scripting.Update -= OnUpdate;
+            if (window != null)
+                window.MouseUp -= OnMouseUp;
+            if (_dragSourceWindow != null)
+                _dragSourceWindow.MouseUp -= OnMouseUp;
 
             RemoveDockHints();
 
-            //FlaxEngine.Input.MouseMove -= OnMouseMove;
-            FlaxEngine.Scripting.Update -= OnUpdate;
-            if (_toMove?.Window?.Window)
-                _toMove.Window.Window.MouseUp -= OnMouseUp;
-
-            if (_dragSourceWindow != null)
-                _dragSourceWindow.MouseUp -= OnMouseUp; // The mouse up event is sent to the source window on Windows
-
             if (_toMove == null)
                 return;
 
-            if (_toMove.Window != null)
-                _toMove.Window.Window.Opacity = 1.0f;
+            if (window != null)
+            {
+                window.Opacity = 1.0f;
+                window.IsAlwaysOnTop = false;
+                window.BringToFront();
+            }
 
             // 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();
@@ -224,88 +160,38 @@ namespace FlaxEditor.GUI.Docking
         }
 
         /// <summary>
-        /// Creates the new dragging hit window.
+        /// Start dragging a floating dock panel.
         /// </summary>
         /// <param name="toMove">Floating dock panel to move.</param>
         /// <returns>The dock hint window object.</returns>
-        public static DockHintWindow Create(FloatWindowDockPanel toMove)
+        public static WindowDragHelper StartDragging(FloatWindowDockPanel toMove)
         {
             if (toMove == null)
                 throw new ArgumentNullException();
 
-            return new DockHintWindow(toMove, null);
+            return new WindowDragHelper(toMove, null);
         }
 
         /// <summary>
-        /// Creates the new dragging hit window.
+        /// Start dragging a docked panel into a floating window.
         /// </summary>
         /// <param name="toMove">Dock window to move.</param>
         /// <returns>The dock hint window object.</returns>
-        public static DockHintWindow Create(DockWindow toMove, Window dragSourceWindow)
+        public static WindowDragHelper StartDragging(DockWindow toMove, Window dragSourceWindow)
         {
             if (toMove == null)
                 throw new ArgumentNullException();
 
-            // Show floating
+            // Create floating window
             toMove.CreateFloating();
 
-            // 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 window = (WindowRootControl)toMove.Root;
             var floatingPanelToMove = window.GetChild(0) as FloatWindowDockPanel;
 
-            return new DockHintWindow(floatingPanelToMove, dragSourceWindow);
+            return new WindowDragHelper(floatingPanelToMove, dragSourceWindow);
         }
 
-        /// <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;
-
-            //Editor.Log($"_dragOffset: {_dragOffset}, mouse: {mouseScreenPosition}, basewinpos: {baseWinPos}");
-        }
-
-        DockHintControl _dockHintDown;
-        DockHintControl _dockHintUp;
-        DockHintControl _dockHintLeft;
-        DockHintControl _dockHintRight;
-        DockHintControl _dockHintCenter;
         private void AddDockHints()
         {
             if (_toDock == null)
@@ -320,14 +206,15 @@ namespace FlaxEditor.GUI.Docking
             _dockHintRight = AddHintControl(new Float2(1, 0.5f));
             _dockHintCenter = AddHintControl(new Float2(0.5f, 0.5f));
 
-            DockHintControl AddHintControl(Float2 pivot)
+            Control AddHintControl(Float2 pivot)
             {
-                DockHintControl hintControl = _toDock.AddChild<DockHintControl>();
-                hintControl.Size = new Float2(Proxy.HintWindowsSize);
+                Control hintControl = _toDock.AddChild<Control>();
+                hintControl.AnchorPreset = AnchorPresets.StretchAll;
+                hintControl.Offsets = Margin.Zero;
+                hintControl.Size = new Float2(HintControlSize);
                 hintControl.BackgroundColor = Style.Current.DragWindow.AlphaMultiplied(0.6f);
                 hintControl.Pivot = pivot;
                 hintControl.PivotRelative = true;
-                //.SetAnchorPreset(AnchorPresets.StretchAll, true);
                 return hintControl;
             }
         }
@@ -354,9 +241,8 @@ namespace FlaxEditor.GUI.Docking
             _mouse = Platform.MousePosition;
 
             // Check intersection with any dock panel
-            var uiMouse = _mouse;
             DockPanel dockPanel = null;
-            if (_toMove.MasterPanel.HitTest(ref uiMouse, _toMove, out var hitResults))
+            if (_toMove.MasterPanel.HitTest(ref _mouse, _toMove, out var hitResults))
             {
                 dockPanel = hitResults[0];
 
@@ -392,17 +278,16 @@ namespace FlaxEditor.GUI.Docking
 
                 // Make sure the all the dock hint areas are not under other windows
                 _toDock?.RootWindow.Window.BringToFront();
-                //_toMove.RootWindow.Window.BringToFront(); // Doesn't work on X11
 
                 // Make the dragged window transparent when dock hints are visible
-                _toMove.Window.Window.Opacity = _toDock == null ? 1.0f : 0.4f;
+                _toMove.Window.Window.Opacity = _toDock == null ? 1.0f : DragWindowOpacity;
             }
             
             // Check dock state to use
             bool showProxyHints = _toDock != null;
             bool showBorderHints = showProxyHints;
             bool showCenterHint = showProxyHints;
-            DockHintControl hoveredHintControl = null;
+            Control hoveredHintControl = null;
             Float2 hoveredSizeOverride = Float2.Zero;
             if (showProxyHints)
             {
@@ -421,9 +306,9 @@ namespace FlaxEditor.GUI.Docking
                 var size = _rectDock.Size / Platform.DpiScale;
                 var offset = _toDock.PointFromScreen(_rectDock.Location);
                 var borderMargin = 4.0f;
-                var hintWindowsSize = Proxy.HintWindowsSize;
+                var hintWindowsSize = HintControlSize;
                 var hintWindowsSize2 = hintWindowsSize * 0.5f;
-                var hintPreviewSize = new Float2(Math.Max(Proxy.HintWindowsSize * 2, size.X * 0.5f), Math.Max(Proxy.HintWindowsSize * 2, size.Y * 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;
@@ -432,7 +317,7 @@ namespace FlaxEditor.GUI.Docking
                 _rRight = new Rectangle(size.X - hintWindowsSize - borderMargin, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
                 _rCenter = new Rectangle(centerX - hintWindowsSize2, centerY - hintWindowsSize2, hintWindowsSize, hintWindowsSize) + offset;
 
-                // Hit test
+                // Hit test, and calculate the approximation for filled area when hovered over the hint
                 DockState toSet = DockState.Float;
                 if (showBorderHints)
                 {
@@ -468,9 +353,6 @@ namespace FlaxEditor.GUI.Docking
                     hoveredSizeOverride = new Float2(size.X, size.Y);
                 }
 
-                //if (toSet != DockState.Float)
-                    
-                
                 _toSet = toSet;
             }
             else
@@ -478,52 +360,37 @@ namespace FlaxEditor.GUI.Docking
                 _toSet = DockState.Float;
             }
             
-            Editor.Log($"docking: {_toSet}, pos: {_mouse}");
-
-            // Calculate proxy/dock/window rectangles
-            if (_toDock == null)
-            {
-                // Floating window over nothing
-                //_rectWindow = new Rectangle(_mouse - _dragOffset, _defaultWindowSize);
-                if (hoveredHintControl != null)
-                    hoveredHintControl.BackgroundColor = Color.Green;
-            }
-            else
+            // Update sizes and opacity of hint controls
+            if (_toDock != null)
             {
                 if (hoveredHintControl != _dockHintDown)
                 {
-                    _dockHintDown.Size = new Float2(Proxy.HintWindowsSize);
+                    _dockHintDown.Size = new Float2(HintControlSize);
                     _dockHintDown.BackgroundColor = Style.Current.DragWindow.AlphaMultiplied(0.6f);
                 }
                 if (hoveredHintControl != _dockHintLeft)
                 {
-                    _dockHintLeft.Size = new Float2(Proxy.HintWindowsSize);
+                    _dockHintLeft.Size = new Float2(HintControlSize);
                     _dockHintLeft.BackgroundColor = Style.Current.DragWindow.AlphaMultiplied(0.6f);
                 }
                 if (hoveredHintControl != _dockHintRight)
                 {
-                    _dockHintRight.Size = new Float2(Proxy.HintWindowsSize);
+                    _dockHintRight.Size = new Float2(HintControlSize);
                     _dockHintRight.BackgroundColor = Style.Current.DragWindow.AlphaMultiplied(0.6f);
                 }
                 if (hoveredHintControl != _dockHintUp)
                 {
-                    _dockHintUp.Size = new Float2(Proxy.HintWindowsSize);
+                    _dockHintUp.Size = new Float2(HintControlSize);
                     _dockHintUp.BackgroundColor = Style.Current.DragWindow.AlphaMultiplied(0.6f);
                 }
                 if (hoveredHintControl != _dockHintCenter)
                 {
-                    _dockHintCenter.Size = new Float2(Proxy.HintWindowsSize);
+                    _dockHintCenter.Size = new Float2(HintControlSize);
                     _dockHintCenter.BackgroundColor = Style.Current.DragWindow.AlphaMultiplied(0.6f);
                 }
-                if (_toSet == DockState.Float)
+
+                if (_toSet != DockState.Float)
                 {
-                    // Floating window over dock panel
-                    if (hoveredHintControl != null)
-                        hoveredHintControl.BackgroundColor = Color.Red;
-                }
-                else
-                {
-                    // Use only part of the dock panel to show hint
                     if (hoveredHintControl != null)
                     {
                         hoveredHintControl.BackgroundColor = Style.Current.DragWindow.AlphaMultiplied(1.0f);
@@ -532,6 +399,7 @@ namespace FlaxEditor.GUI.Docking
                 }
             }
 
+            // Update hint controls visibility and location
             if (showProxyHints)
             {
                 if (hoveredHintControl != _dockHintDown)
@@ -545,226 +413,33 @@ namespace FlaxEditor.GUI.Docking
                 if (hoveredHintControl != _dockHintCenter)
                     _dockHintCenter.Location = _rCenter.Location;
                 
-                // Update proxy hint windows visibility
                 _dockHintDown.Visible = showProxyHints & showBorderHints;
                 _dockHintLeft.Visible = showProxyHints & showBorderHints;
                 _dockHintRight.Visible = showProxyHints & showBorderHints;
                 _dockHintUp.Visible = showProxyHints & showBorderHints;
                 _dockHintCenter.Visible = showProxyHints & showCenterHint;
             }
-
-            // Update proxy window
-            //Proxy.Window.ClientBounds = _rectWindow;
         }
 
         private void OnMouseUp(ref Float2 location, MouseButton button, ref bool handled)
         {
-            Editor.Log("DockHintWindow.OnMouseUp");
             if (button == MouseButton.Left)
-            {
                 Dispose();
         }
-        }
 
         private void OnUpdate()
         {
-            //Editor.Log("OnUpdate");
             var mousePos = Platform.MousePosition;
             if (_mouse != mousePos)
-            {
-                //Editor.Log($"mouse pos {_mouse} -> {mousePos}");
                 OnMouseMove(mousePos);
         }
-        }
         
         private void OnMouseMove(Float2 mousePos)
         {
-            if (_moveWindow)
-            {
+            if (_dragSourceWindow != null)
                 _toMove.Window.Window.Position = mousePos - _dragOffset;
-            }
-            //Editor.Log("OnMouseMove");
-            // 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();
-        }
-        
-        public class DockHintControl : Control
-        {
-            public DockHintControl()
-            {
-                AnchorPreset = AnchorPresets.StretchAll;
-                Offsets = Margin.Zero;
-            }
-        }
-
-        /// <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.Type = WindowType.Utility;
-                    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.DragWindow;
-                }
-                else
-                {
-                    // Resize proxy
-                    Window.ClientSize = initSize;
-                }
-
-                InitHitProxy();
-            }
-
-            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.Type = WindowType.Utility;
-                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.DragWindow;
-            }
-
-            /// <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/Modules/UIModule.cs

@@ -16,7 +16,7 @@ using FlaxEditor.Windows;
 using FlaxEngine;
 using FlaxEngine.GUI;
 using FlaxEngine.Json;
-using DockHintWindow = FlaxEditor.GUI.Docking.DockHintWindow;
+using WindowDragHelper = FlaxEditor.GUI.Docking.WindowDragHelper;
 using MasterDockPanel = FlaxEditor.GUI.Docking.MasterDockPanel;
 using FlaxEditor.Content.Settings;
 using FlaxEditor.Options;
@@ -456,13 +456,6 @@ 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);

Source/Engine/Platform/Base/WindowBase.cpp

@@ -164,6 +164,15 @@ void WindowBase::SetIsVisible(bool isVisible)
     }
 }
 
+bool WindowBase::IsAlwaysOnTop() const
+{
+    return false;
+}
+
+void WindowBase::SetIsAlwaysOnTop(bool isAlwaysOnTop)
+{
+}
+
 String WindowBase::ToString() const
 {
     return GetTitle();

Source/Engine/Platform/Base/WindowBase.h

@@ -157,6 +157,17 @@ public:
         return _maximized;
     }
 
+    /// <summary>
+    /// Gets a value that indicates whether a window is always on top of other windows.
+    /// </summary>
+    API_PROPERTY() virtual bool IsAlwaysOnTop() const;
+
+    /// <summary>
+    /// Sets a value that indicates whether a window is always on top of other windows.
+    /// </summary>
+    /// <param name="isAlwaysOnTop">True if always on top.</param>
+    API_PROPERTY() virtual void SetIsAlwaysOnTop(bool isAlwaysOnTop);
+
     /// <summary>
     /// Gets the native window handle.
     /// </summary>

Source/Engine/Platform/SDL/SDLInput.cpp

@@ -514,12 +514,6 @@ bool SDLInput::HandleEvent(SDLWindow* window, SDL_Event& event)
         else
         {
             const Float2 mousePos = window->ClientToScreen({ event.motion.x, event.motion.y });
-            Int2 p;
-            Float2 wp = window->ClientToScreen({0, 0});
-            //SDL_GetWindowPosition(window->GetSDLWindow(), &p.X, &p.Y);
-            p.X = wp.X;
-            p.Y = wp.Y;
-            //LOG(Info, "motion {},{}, mouse: {}, win: {}, winpos {},{}", event.motion.x, event.motion.y, mousePos, String(window->GetTitle()), p.X, p.Y);
             Input::Mouse->OnMouseMove(mousePos, window);
         }
         return true;

Source/Engine/Platform/SDL/SDLPlatform.cpp

@@ -77,21 +77,24 @@ bool SDLPlatform::Init()
     SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_WARP_MOTION, "0");
     SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_CURSOR_VISIBLE, "1"); // Needed for tracking mode
     SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_MODE_CENTER, "0"); // 
+    SDL_SetHint(SDL_HINT_MOUSE_DOUBLE_CLICK_RADIUS, "8"); // Reduce the default mouse double-click radius
 
     //SDL_SetHint(SDL_HINT_MOUSE_RELATIVE_MODE_WARP, "1"); // Disables raw mouse input
     SDL_SetHint(SDL_HINT_WINDOWS_RAW_KEYBOARD, "1");
 
     SDL_SetHint(SDL_HINT_VIDEO_WAYLAND_SCALE_TO_DISPLAY, "1");
 
+#if PLATFORM_WINDOWS
     // Disable SDL clipboard support
-    /*SDL_SetEventEnabled(SDL_EVENT_CLIPBOARD_UPDATE, false);
+    SDL_SetEventEnabled(SDL_EVENT_CLIPBOARD_UPDATE, false);
 
     // Disable SDL drag and drop support
     SDL_SetEventEnabled(SDL_EVENT_DROP_FILE, false);
     SDL_SetEventEnabled(SDL_EVENT_DROP_TEXT, false);
     SDL_SetEventEnabled(SDL_EVENT_DROP_BEGIN, false);
     SDL_SetEventEnabled(SDL_EVENT_DROP_COMPLETE, false);
-    SDL_SetEventEnabled(SDL_EVENT_DROP_POSITION, false);*/
+    SDL_SetEventEnabled(SDL_EVENT_DROP_POSITION, false);
+#endif
 
     //if (InitPlatform())
     //    return true;
@@ -217,9 +220,15 @@ void SDLPlatform::Tick()
             if (draggedWindow == nullptr)
                 return true;
 
+            // When the window is being dragged on Windows, the internal message loop is blocking
+            // the SDL event queue. We need to handle all relevant events in this event watch callback
+            // to ensure dragging related functionality doesn't break due to engine not getting updated.
+            // This also happens to fix the engine freezing during the dragging operation.
+
             SDLWindow* window = SDLWindow::GetWindowFromEvent(*event);
             if (event->type == SDL_EVENT_WINDOW_EXPOSED)
             {
+                // The internal timer is sending exposed events every ~16ms
                 Engine::OnUpdate();//Scripting::Update(); // For docking updates
                 Engine::OnDraw();
                 return false;
@@ -304,11 +313,6 @@ void SDLPlatform::Tick()
             buttonUpEvent.motion.x = mousePosition.X;
             buttonUpEvent.motion.y = mousePosition.Y;
             draggedWindow->HandleEvent(buttonUpEvent);
-            //SDL_PushEvent(&buttonUpEvent);
-
-            SDL_SetWindowAlwaysOnTop(draggedWindow->GetSDLWindow(), false);
-            draggedWindow->BringToFront();
-            
             draggedWindow = nullptr;
         }
     }

Source/Engine/Platform/SDL/SDLWindow.cpp

@@ -67,6 +67,11 @@ void GetRelativeWindowOffset(WindowType type, SDLWindow* parentWindow, Int2& pos
 Int2 GetSDLWindowScreenPosition(const SDLWindow* window);
 void SetSDLWindowScreenPosition(const SDLWindow* window, const int x, const int y);
 
+bool IsPopupWindow(WindowType type)
+{
+    return type == WindowType::Popup || type == WindowType::Tooltip;
+}
+
 class SDLDropFilesData : public IGuiData
 {
 public:
@@ -823,9 +828,9 @@ void SDLWindow::Show()
     else if (_settings.Parent == nullptr)
         BringToFront();
     
-    // Reused top-most windows (DockHintWindow) doesn't stay on top for some reason
-    if (_settings.IsTopmost && _settings.Type != WindowType::Tooltip)
-        SDL_SetWindowAlwaysOnTop(_window, true);
+    // Reused top-most windows doesn't stay on top for some reason
+    if (_settings.IsTopmost && !IsPopupWindow(_settings.Type))
+        SetIsAlwaysOnTop(true);
 
     if (_isTrackingMouse)
     {
@@ -980,11 +985,6 @@ void SDLWindow::SetClientBounds(const Rectangle& clientArea)
     SDL_SetWindowSize(_window, newW, newH);
 }
 
-bool IsPopupWindow(WindowType type)
-{
-    return type == WindowType::Popup || type == WindowType::Tooltip;
-}
-
 void GetRelativeWindowOffset(WindowType type, SDLWindow* parentWindow, Int2& positionOffset)
 {
     if (!IsPopupWindow(type))
@@ -1051,12 +1051,25 @@ void SDLWindow::SetIsFullscreen(bool isFullscreen)
     if (!isFullscreen)
     {
         // The window is set to always-on-top for some reason when leaving fullscreen
-        SDL_SetWindowAlwaysOnTop(_window, false);
+        SetIsAlwaysOnTop(false);
     }
 
     WindowBase::SetIsFullscreen(isFullscreen);
 }
 
+bool SDLWindow::IsAlwaysOnTop() const
+{
+    SDL_WindowFlags flags = SDL_GetWindowFlags(_window);
+    return (flags & SDL_WINDOW_ALWAYS_ON_TOP) != 0;
+}
+
+void SDLWindow::SetIsAlwaysOnTop(bool isAlwaysOnTop)
+{
+    if (!SDL_SetWindowAlwaysOnTop(_window, isAlwaysOnTop))
+        LOG(Warning, "SDL_SetWindowAlwaysOnTop failed: {0}", String(SDL_GetError()));
+    // Not sure if this should change _settings.IsTopmost to reflect the new value?
+}
+
 Float2 SDLWindow::GetPosition() const
 {
     Int2 topLeftBorder;
@@ -1332,7 +1345,6 @@ DragDropEffect SDLWindow::DoDragDrop(const StringView& data, const Float2& offse
     else
 #endif
     {
-        SDL_SetWindowAlwaysOnTop(_window, true);
         Show();
         
         //draggingActive = true;

Source/Engine/Platform/SDL/SDLWindow.h

@@ -91,6 +91,8 @@ public:
     void SetPosition(const Float2& position) override;
     void SetClientPosition(const Float2& position) override;
     void SetIsFullscreen(bool isFullscreen) override;
+    bool IsAlwaysOnTop() const override;
+    void SetIsAlwaysOnTop(bool isAlwaysOnTop) override;
     Float2 GetPosition() const override;
     Float2 GetSize() const override;
     Float2 GetClientSize() const override;

Source/Engine/Platform/Windows/WindowsWindow.DragDrop.cpp

@@ -601,7 +601,8 @@ DragDropEffect Window::DoDragDrop(const StringView& data)
         ::POINT point;
         ::GetCursorPos(&point);
 #if PLATFORM_SDL
-        Input::Mouse->OnMouseUp(Float2((float)point.x, (float)point.y), MouseButton::Left, (Window*)this);
+        // Reset the internal button state in SDL
+        SendMessageA((HWND)_handle, WM_LBUTTONUP, 0, MAKELPARAM(point.x, point.y));
 #else
         Input::Mouse->OnMouseUp(Float2((float)point.x, (float)point.y), MouseButton::Left, this);
 #endif

Source/Tools/Flax.Build/Deps/Dependencies/SDL.cs

@@ -88,7 +88,8 @@ namespace Flax.Deps.Dependencies
                 Path.Combine(root, "include", "SDL3"),
             };
 
-            CloneGitRepoFastSince(root, "https://github.com/libsdl-org/SDL", new DateTime(2025, 01, 19));
+            CloneGitRepoFast(root, "https://github.com/libsdl-org/SDL");
+            GitFetch(root);
             GitResetToCommit(root, "819628c6bf8e6c3e5357d7ee4bd2d3d43ddfe052");
 
             foreach (var platform in options.Platforms)

Source/Tools/Flax.Build/Deps/Dependency.cs

@@ -131,6 +131,18 @@ namespace Flax.Deps
             Utilities.DirectoryCopy(src, dst);
         }
 
+        /// <summary>
+        /// Checks if git repository exists at given path.
+        /// </summary>
+        /// <param name="path">The path.</param>
+        public static bool GitRepositoryExists(string path)
+        {
+            Console.WriteLine(path);
+            string dotGitPath = Path.Combine(path, ".git");
+            return Directory.Exists(dotGitPath) ||
+                File.Exists(dotGitPath); // Worktree repository
+        }
+
         /// <summary>
         /// Clones the git repository from the remote url (full repository).
         /// </summary>
@@ -141,7 +153,7 @@ namespace Flax.Deps
         /// <param name="submodules">True if initialize submodules of the repository (recursive).</param>
         public static void CloneGitRepo(string path, string url, string commit = null, string args = null, bool submodules = false)
         {
-            if (!Directory.Exists(Path.Combine(path, ".git")))
+            if (!GitRepositoryExists(path))
             {
                 string cmdLine = string.Format("clone \"{0}\" \"{1}\"", url, path);
                 if (args != null)
@@ -166,7 +178,7 @@ namespace Flax.Deps
         /// <param name="submodules">True if initialize submodules of the repository (recursive).</param>
         public static void CloneGitRepoFast(string path, string url, string args = null, bool submodules = false)
         {
-            if (!Directory.Exists(Path.Combine(path, ".git")))
+            if (!GitRepositoryExists(path))
             {
                 string cmdLine = string.Format("clone \"{0}\" \"{1}\" --depth 1", url, path);
                 if (args != null)
@@ -181,26 +193,15 @@ namespace Flax.Deps
         }
 
         /// <summary>
-        /// Clones the git repository from the remote url.
+        /// Fetches the git repository from remote url.
         /// </summary>
-        /// <param name="path">The local path for close.</param>
-        /// <param name="url">The remote url.</param>
-        /// <param name="time">The time after history is included in the local repository.</param>
-        /// <param name="args">The custom arguments to add to the clone command.</param>
-        /// <param name="submodules">True if initialize submodules of the repository (recursive).</param>
-        public static void CloneGitRepoFastSince(string path, string url, DateTime time, string args = null, bool submodules = false)
+        /// <param name="path">The git repository path</param>
+        /// <param name="url">The remote url</param>
+        public static void GitFetch(string path)
         {
-            if (!Directory.Exists(Path.Combine(path, ".git")))
+            if (GitRepositoryExists(path))
             {
-                string cmdLine = string.Format("clone \"{0}\" \"{1}\" --shallow-since={2}", url, path, time.ToString("s"));
-                if (args != null)
-                    cmdLine += " " + args;
-                if (submodules)
-                    cmdLine += " --recurse-submodules";
-
-                Utilities.Run("git", cmdLine, null, path, Utilities.RunOptions.DefaultTool);
-                if (submodules)
-                    Utilities.Run("git", "submodule update --init --recursive", null, path, Utilities.RunOptions.DefaultTool);
+                Utilities.Run("git", $"fetch \"{path}\"", null, path, Utilities.RunOptions.DefaultTool);
             }
         }
 
@@ -215,7 +216,7 @@ namespace Flax.Deps
         /// <param name="submodules">True if initialize submodules of the repository (recursive).</param>
         public static void CloneGitRepoSingleBranch(string path, string url, string branch, string commit = null, string args = null, bool submodules = false)
         {
-            if (!Directory.Exists(Path.Combine(path, ".git")))
+            if (!GitRepositoryExists(path))
             {
                 string cmdLine = string.Format("clone --single-branch --branch {2} \"{0}\" \"{1}\"", url, path, branch);
                 if (commit == null)