Fix VirtualView null exceptions and popup removal race condition

- Fix RemoveAsync race condition: close popup before disconnecting handler
- Add null-safe VirtualView access with try-catch on all platforms
- Properly unsubscribe SizeChanged event in PopupPageHandler
- Fix Android Window type ambiguity with fully qualified name
- Fix README path in csproj

The root cause was layout events firing during popup removal while
the handler was being disconnected. Now we close the popup first
to stop events, then clean up.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Mopups/Mopups.Maui/Mopups.csproj

@@ -110,6 +110,6 @@
 
 	<ItemGroup>
 		<None Include="icon.png" Pack="true" PackagePath="\" />
-		<None Include="..\..\..\..\README.md" Pack="true" PackagePath="\" />
+		<None Include="..\..\README.md" Pack="true" PackagePath="\" />
 	</ItemGroup>
 </Project>

Mopups/Mopups.Maui/Platforms/Android/Impl/AndroidMopups.cs

@@ -44,7 +44,7 @@ public class AndroidMopups : IPopupPlatform
         return AddAsync(page, null);
     }
 
-    public Task AddAsync(PopupPage page, Window? targetWindow)
+    public Task AddAsync(PopupPage page, Microsoft.Maui.Controls.Window? targetWindow)
     {
         HandleAccessibility(true, page.DisableAndroidAccessibilityHandling, page);
 

Mopups/Mopups.Maui/Platforms/MacCatalyst/Handler/PopupPageRenderer.cs

@@ -59,7 +59,11 @@ namespace Mopups.Platforms.MacCatalyst
 
             if (Equals(subview, view))
             {
-                ((PopupPage)Handler.VirtualView).SendBackgroundClick();
+                try
+                {
+                    (Handler.VirtualView as PopupPage)?.SendBackgroundClick();
+                }
+                catch (InvalidOperationException) { }
             }
         }
 
@@ -74,30 +78,36 @@ namespace Mopups.Platforms.MacCatalyst
 
             void UpdateSize(PopupPageRenderer handler)
             {
-                var currentElement = ((PopupPage)Handler.VirtualView);
+                try
-
-                if (handler.Handler.PlatformView?.Superview?.Frame == null || currentElement == null)
-                    return;
-
-                var superviewFrame = handler.Handler.PlatformView.Superview.Frame;
-                var applicationFrame = UIScreen.MainScreen.ApplicationFrame;
-
-                var systemPadding = new Thickness
                 {
-                    Left = applicationFrame.Left,
+                    var currentElement = Handler.VirtualView as PopupPage;
-                    Top = applicationFrame.Top,
-                    Right = applicationFrame.Right - applicationFrame.Width - applicationFrame.Left,
-                    Bottom = applicationFrame.Bottom - applicationFrame.Height - applicationFrame.Top + handler.KeyboardBounds.Height
-                };
 
-                if ((handler.Handler.VirtualView.Width != superviewFrame.Width && handler.Handler.VirtualView.Height != superviewFrame.Height)
+                    if (handler.Handler.PlatformView?.Superview?.Frame == null || currentElement == null)
-                    || currentElement.SystemPadding.Bottom != systemPadding.Bottom)
+                        return;
-                {
+
-                    currentElement.BatchBegin();
+                    var superviewFrame = handler.Handler.PlatformView.Superview.Frame;
-                    currentElement.SystemPadding = systemPadding;
+                    var applicationFrame = UIScreen.MainScreen.ApplicationFrame;
-                    currentElement.Layout(new Rect(currentElement.X, currentElement.Y, superviewFrame.Width, superviewFrame.Height));
+
-                    currentElement.BatchCommit();
+                    var systemPadding = new Thickness
+                    {
+                        Left = applicationFrame.Left,
+                        Top = applicationFrame.Top,
+                        Right = applicationFrame.Right - applicationFrame.Width - applicationFrame.Left,
+                        Bottom = applicationFrame.Bottom - applicationFrame.Height - applicationFrame.Top + handler.KeyboardBounds.Height
+                    };
+
+                    var virtualView = handler.Handler.VirtualView;
+                    if (virtualView != null &&
+                        ((virtualView.Width != superviewFrame.Width && virtualView.Height != superviewFrame.Height)
+                        || currentElement.SystemPadding.Bottom != systemPadding.Bottom))
+                    {
+                        currentElement.BatchBegin();
+                        currentElement.SystemPadding = systemPadding;
+                        currentElement.Layout(new Rect(currentElement.X, currentElement.Y, superviewFrame.Width, superviewFrame.Height));
+                        currentElement.BatchCommit();
+                    }
                 }
+                catch (InvalidOperationException) { }
             }
         }
 

Mopups/Mopups.Maui/Platforms/Windows/Handler/PopupPageHandler.cs

@@ -6,6 +6,8 @@ namespace Mopups.Platforms.Windows
 {
     public class PopupPageHandler : PageHandler
     {
+        private Microsoft.UI.Xaml.SizeChangedEventHandler? _sizeChangedHandler;
+
         public PopupPageHandler()
         {
         }
@@ -14,7 +16,25 @@ namespace Mopups.Platforms.Windows
         {
             base.ConnectHandler(platformView);
 
-            PlatformView.SizeChanged += (_, e) => VirtualView.ComputeDesiredSize(e.NewSize.Width, e.NewSize.Height);
+            _sizeChangedHandler = (_, e) =>
+            {
+                try
+                {
+                    VirtualView?.ComputeDesiredSize(e.NewSize.Width, e.NewSize.Height);
+                }
+                catch (InvalidOperationException) { }
+            };
+            PlatformView.SizeChanged += _sizeChangedHandler;
+        }
+
+        protected override void DisconnectHandler(ContentPanel platformView)
+        {
+            if (_sizeChangedHandler != null)
+            {
+                platformView.SizeChanged -= _sizeChangedHandler;
+                _sizeChangedHandler = null;
+            }
+            base.DisconnectHandler(platformView);
         }
 
         protected override ContentPanel CreatePlatformView()

Mopups/Mopups.Maui/Platforms/Windows/Handler/PopupPageRenderer.cs

@@ -15,7 +15,20 @@ namespace Mopups.Platforms.Windows
 
         internal WinPopup? Container { get; private set; }
 
-        private PopupPage CurrentElement => (PopupPage)handler.VirtualView;
+        private PopupPage? CurrentElement
+        {
+            get
+            {
+                try
+                {
+                    return handler.VirtualView as PopupPage;
+                }
+                catch (InvalidOperationException)
+                {
+                    return null;
+                }
+            }
+        }
 
         public PopupPageRenderer(PopupPageHandler handler)
         {
@@ -92,7 +105,7 @@ namespace Mopups.Platforms.Windows
         {
             if ((e.OriginalSource as PopupPageRenderer) == this)
             {
-                CurrentElement.SendBackgroundClick();
+                CurrentElement?.SendBackgroundClick();
             }
         }
 

Mopups/Mopups.Maui/Platforms/Windows/Impl/PopupPlatformWindows.cs

@@ -56,34 +56,33 @@ namespace Mopups.Windows.Implementation
 
         public async Task AddAsync(PopupPage page, Window? window)
         {
-            var mainPage = Application.Current.MainPage;
+            // Use target window's page if provided, otherwise fall back to MainPage
-            mainPage.AddLogicalChild(page);
+            Page parentPage;
-
+            IMauiContext mauiContext;
-            var popup = new global::Microsoft.UI.Xaml.Controls.Primitives.Popup();
-
-            // Use TOPLATFORM to create your handlers
-            // I'd recommend wiring up all your services through ConfigureMopups
-            // builder.Services.AddScoped<IPopupPlatform, PopupPlatform>();
-            // builder.Services.AddScoped<IPopupNavigation, PopupNavigation>();
-            // Then you can use contructor resolution instead of singletons
-            // But I figured we could do that in a later PR and just work on windows here
-
-            var renderer = (PopupPageRenderer)page.ToPlatform(mainPage.Handler.MauiContext);
-            renderer.Prepare(popup);
-            popup.Child = renderer;
-
-            // https://github.com/microsoft/microsoft-ui-xaml/issues/3389
-            // Use the specified window's XamlRoot if provided, otherwise fall back to main window
             Microsoft.UI.Xaml.Window nativeWindow;
-            if (window?.Handler?.PlatformView is Microsoft.UI.Xaml.Window targetWindow)
+
+            if (window?.Handler?.PlatformView is Microsoft.UI.Xaml.Window targetWindow && window.Page != null)
             {
+                parentPage = window.Page;
+                mauiContext = window.Handler.MauiContext!;
                 nativeWindow = targetWindow;
             }
             else
             {
-                nativeWindow = mainPage.Handler.MauiContext.Services.GetService<Microsoft.UI.Xaml.Window>();
+                parentPage = Application.Current.MainPage;
+                mauiContext = parentPage.Handler.MauiContext;
+                nativeWindow = mauiContext.Services.GetService<Microsoft.UI.Xaml.Window>();
             }
 
+            parentPage.AddLogicalChild(page);
+
+            var popup = new global::Microsoft.UI.Xaml.Controls.Primitives.Popup();
+
+            var renderer = (PopupPageRenderer)page.ToPlatform(mauiContext);
+            renderer.Prepare(popup);
+            popup.Child = renderer;
+
+            // https://github.com/microsoft/microsoft-ui-xaml/issues/3389
             popup.XamlRoot = nativeWindow.Content.XamlRoot;
             popup.IsOpen = true;
             page.ForceLayout();
@@ -96,17 +95,35 @@ namespace Mopups.Windows.Implementation
             if (page == null)
                 throw new Exception("Popup page is null");
 
-            var renderer = (PopupPageRenderer)page.ToPlatform(Application.Current.MainPage.Handler.MauiContext);
+            // Get the handler before we start cleanup
-            var popup = renderer.Container;
+            var handler = page.Handler;
+            if (handler == null)
+            {
+                // Already cleaned up
+                page.Parent?.RemoveLogicalChild(page);
+                return;
+            }
+
+            var renderer = handler.PlatformView as PopupPageRenderer;
+            var popup = renderer?.Container;
 
             if (popup != null)
             {
-                renderer.Destroy();
+                // First close the popup to stop layout events
-
-                Cleanup(page);
-                page.Parent?.RemoveLogicalChild(page);
-                popup.Child = null;
                 popup.IsOpen = false;
+                popup.Child = null;
+
+                // Now safe to destroy and cleanup
+                renderer?.Destroy();
+                page.Parent?.RemoveLogicalChild(page);
+
+                // Disconnect handler last
+                Cleanup(page);
+            }
+            else
+            {
+                page.Parent?.RemoveLogicalChild(page);
+                Cleanup(page);
             }
 
             await Task.Delay(5);

Mopups/Mopups.Maui/Platforms/iOS/Handler/PopupPageRenderer.cs

@@ -59,7 +59,11 @@ namespace Mopups.Platforms.iOS
 
             if (Equals(subview, view))
             {
-                ((PopupPage)Handler.VirtualView).SendBackgroundClick();
+                try
+                {
+                    (Handler.VirtualView as PopupPage)?.SendBackgroundClick();
+                }
+                catch (InvalidOperationException) { }
             }
         }
 
@@ -74,30 +78,36 @@ namespace Mopups.Platforms.iOS
 
             void UpdateSize(PopupPageRenderer handler)
             {
-                var currentElement = ((PopupPage)Handler.VirtualView);
+                try
-
-                if (handler.Handler.PlatformView?.Superview?.Frame == null || currentElement == null)
-                    return;
-
-                var superviewFrame = handler.Handler.PlatformView.Superview.Frame;
-                var applicationFrame = UIScreen.MainScreen.ApplicationFrame;
-
-                var systemPadding = new Thickness
                 {
-                    Left = applicationFrame.Left,
+                    var currentElement = Handler.VirtualView as PopupPage;
-                    Top = applicationFrame.Top,
-                    Right = applicationFrame.Right - applicationFrame.Width - applicationFrame.Left,
-                    Bottom = applicationFrame.Bottom - applicationFrame.Height - applicationFrame.Top + handler.KeyboardBounds.Height
-                };
 
-                if ((handler.Handler.VirtualView.Width != superviewFrame.Width && handler.Handler.VirtualView.Height != superviewFrame.Height)
+                    if (handler.Handler.PlatformView?.Superview?.Frame == null || currentElement == null)
-                    || currentElement.SystemPadding.Bottom != systemPadding.Bottom)
+                        return;
-                {
+
-                    currentElement.BatchBegin();
+                    var superviewFrame = handler.Handler.PlatformView.Superview.Frame;
-                    currentElement.SystemPadding = systemPadding;
+                    var applicationFrame = UIScreen.MainScreen.ApplicationFrame;
-                    currentElement.Layout(new Rect(currentElement.X, currentElement.Y, superviewFrame.Width, superviewFrame.Height));
+
-                    currentElement.BatchCommit();
+                    var systemPadding = new Thickness
+                    {
+                        Left = applicationFrame.Left,
+                        Top = applicationFrame.Top,
+                        Right = applicationFrame.Right - applicationFrame.Width - applicationFrame.Left,
+                        Bottom = applicationFrame.Bottom - applicationFrame.Height - applicationFrame.Top + handler.KeyboardBounds.Height
+                    };
+
+                    var virtualView = handler.Handler.VirtualView;
+                    if (virtualView != null &&
+                        ((virtualView.Width != superviewFrame.Width && virtualView.Height != superviewFrame.Height)
+                        || currentElement.SystemPadding.Bottom != systemPadding.Bottom))
+                    {
+                        currentElement.BatchBegin();
+                        currentElement.SystemPadding = systemPadding;
+                        currentElement.Layout(new Rect(currentElement.X, currentElement.Y, superviewFrame.Width, superviewFrame.Height));
+                        currentElement.BatchCommit();
+                    }
                 }
+                catch (InvalidOperationException) { }
             }
         }