Properly notify the TopLevel before destroying render targets

src/Avalonia.Controls/TopLevel.cs

@@ -527,6 +527,13 @@ namespace Avalonia.Controls
         /// </summary>
         protected virtual void HandleClosed()
         {
+            Renderer.SceneInvalidated -= SceneInvalidated;
+            // We need to wait for the renderer to complete any in-flight operations
+            Renderer.Dispose();
+            
+            // The PlatformImpl is completely invalid at this point
+            PlatformImpl = null;
+            
             if (_globalStyles is object)
             {
                 _globalStyles.GlobalStylesAdded -= ((IStyleHost)this).StylesAdded;
@@ -536,10 +543,7 @@ namespace Avalonia.Controls
             {
                 _applicationThemeHost.ActualThemeVariantChanged -= GlobalActualThemeVariantChanged;
             }
-
-            Renderer.SceneInvalidated -= SceneInvalidated;
-            Renderer.Dispose();
-
+            
             _layoutDiagnosticBridge?.Dispose();
             _layoutDiagnosticBridge = null;
 
@@ -547,8 +551,6 @@ namespace Avalonia.Controls
             _pointerOverPreProcessorSubscription?.Dispose();
             _backGestureSubscription?.Dispose();
 
-            PlatformImpl = null;
-
             var logicalArgs = new LogicalTreeAttachmentEventArgs(this, this, null);
             ((ILogical)this).NotifyDetachedFromLogicalTree(logicalArgs);
 

src/Avalonia.X11/X11Window.cs

@@ -48,6 +48,7 @@ namespace Avalonia.X11
         private readonly X11NativeControlHost _nativeControlHost;
         private PixelPoint? _position;
         private PixelSize _realSize;
+        private bool _cleaningUp;
         private IntPtr _handle;
         private IntPtr _xic;
         private IntPtr _renderHandle;
@@ -522,7 +523,7 @@ namespace Avalonia.X11
             else if (ev.type == XEventName.DestroyNotify 
                      && ev.DestroyWindowEvent.window == _handle)
             {
-                Cleanup();
+                Cleanup(true);
             }
             else if (ev.type == XEventName.ClientMessage)
             {
@@ -816,7 +817,7 @@ namespace Avalonia.X11
 
         public void Dispose()
         {
-            Cleanup();            
+            Cleanup(false);            
         }
 
         public virtual object? TryGetFeature(Type featureType)
@@ -849,8 +850,17 @@ namespace Avalonia.X11
             return null;
         }
 
-        private void Cleanup()
+        private void Cleanup(bool fromDestroyNotification)
         {
+            // Prevent reentrancy
+            if(_cleaningUp)
+                return;
+            _cleaningUp = true;
+            
+            // Before doing anything else notify the TopLevel that ITopLevelImpl is no longer valid
+            if (_handle != IntPtr.Zero)
+                Closed?.Invoke();
+            
             if (_rawEventGrouper != null)
             {
                 _rawEventGrouper.Dispose();
@@ -891,7 +901,8 @@ namespace Avalonia.X11
                 Closed?.Invoke();
                 _mouse.Dispose();
                 _touch.Dispose();
-                XDestroyWindow(_x11.Display, handle);
+                if (!fromDestroyNotification)
+                    XDestroyWindow(_x11.Display, handle);
             }
             
             if (_useRenderWindow && _renderHandle != IntPtr.Zero)

src/Windows/Avalonia.Win32/WindowImpl.AppWndProc.cs

@@ -85,6 +85,9 @@ namespace Avalonia.Win32
 
                 case WindowsMessage.WM_DESTROY:
                     {
+                        // The first and foremost thing to do - notify the TopLevel
+                        Closed?.Invoke();
+                        
                         if (UiaCoreTypesApi.IsNetComInteropAvailable)
                         {
                             UiaCoreProviderApi.UiaReturnRawElementProvider(_hwnd, IntPtr.Zero, IntPtr.Zero, null);
@@ -95,6 +98,18 @@ namespace Avalonia.Win32
                         {
                             Imm32InputMethod.Current.ClearLanguageAndWindow();
                         }
+                        
+                        // Cleanup render targets
+                        (_gl as IDisposable)?.Dispose();
+
+                        if (_dropTarget != null)
+                        {
+                            OleContext.Current?.UnregisterDragDrop(Handle);
+                            _dropTarget.Dispose();
+                            _dropTarget = null;
+                        }
+
+                        _framebuffer.Dispose();
 
                         //Window doesn't exist anymore
                         _hwnd = IntPtr.Zero;

src/Windows/Avalonia.Win32/WindowImpl.cs

@@ -624,15 +624,6 @@ namespace Avalonia.Win32
 
         public void Dispose()
         {
-            (_gl as IDisposable)?.Dispose();
-
-            if (_dropTarget != null)
-            {
-                OleContext.Current?.UnregisterDragDrop(Handle);
-                _dropTarget.Dispose();
-                _dropTarget = null;
-            }
-
             if (_hwnd != IntPtr.Zero)
             {
                 // Detect if we are being closed programmatically - this would mean that WM_CLOSE was not called
@@ -645,8 +636,6 @@ namespace Avalonia.Win32
                 DestroyWindow(_hwnd);
                 _hwnd = IntPtr.Zero;
             }
-
-            _framebuffer.Dispose();
         }
 
         public void Invalidate(Rect rect)