Merge pull request #8236 from AvaloniaUI/fix-popup-leak

Fix FlyoutBase/ContextMenu memory leak

src/Avalonia.Controls/ContextMenu.cs

@@ -448,6 +448,11 @@ namespace Avalonia.Controls
             if (sender is Control control
                 && control.ContextMenu is ContextMenu contextMenu)
             {
+                if (contextMenu._popup?.Parent == control)
+                {
+                    ((ISetLogicalParent)contextMenu._popup).SetParent(null);
+                }
+
                 contextMenu.Close();
             }
         }

src/Avalonia.Controls/Flyouts/FlyoutBase.cs

@@ -177,7 +177,8 @@ namespace Avalonia.Controls.Primitives
 
             IsOpen = false;
             Popup.IsOpen = false;
-
+            ((ISetLogicalParent)Popup).SetParent(null);
+            
             // Ensure this isn't active
             _transientDisposable?.Dispose();
             _transientDisposable = null;

tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs

@@ -445,6 +445,27 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void Should_Reset_Popup_Parent_On_Target_Detached()
+        {
+            using (Application())
+            {
+                var userControl = new UserControl();
+                var window = PreparedWindow(userControl);
+                window.Show();
+                
+                var menu = new ContextMenu();
+                userControl.ContextMenu = menu;
+                menu.Open();
+                
+                var popup = Assert.IsType<Popup>(menu.Parent);
+                Assert.NotNull(popup.Parent);
+                
+                window.Content = null;
+                Assert.Null(popup.Parent);
+            }
+        }
+
         [Fact]
         public void Context_Menu_In_Resources_Can_Be_Shared()
         {

tests/Avalonia.Controls.UnitTests/FlyoutTests.cs

@@ -432,6 +432,26 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void Should_Reset_Popup_Parent_On_Target_Detached()
+        {
+            using (CreateServicesWithFocus())
+            {
+                var userControl = new UserControl();
+                var window = PreparedWindow(userControl);
+                window.Show();
+                
+                var flyout = new TestFlyout();
+                flyout.ShowAt(userControl);
+                
+                var popup = Assert.IsType<Popup>(flyout.Popup);
+                Assert.NotNull(popup.Parent);
+                
+                window.Content = null;
+                Assert.Null(popup.Parent);
+            }
+        }
+
         [Fact]
         public void ContextFlyout_Can_Be_Set_In_Styles()
         {
@@ -549,5 +569,10 @@ namespace Avalonia.Controls.UnitTests
                 new PointerPointProperties(RawInputModifiers.None, PointerUpdateKind.LeftButtonPressed),
                 KeyModifiers.None);
         }
+        
+        public class TestFlyout : Flyout
+        {
+            public new Popup Popup => base.Popup;
+        }
     }
 }