Fixes/osx thick titlebar pointer events streaming, (tabs interface) #15696 (#19320)

* Added failing test for OSXThickTitleBar drag events outside thick title area

* MacOS. Added event tracking loop for drag events started in thick titlebar (NSToolbar)

* Review fix: forward events to AppKit during tracking loop (#19320)

native/Avalonia.Native/src/OSX/AvnWindow.mm

@@ -476,8 +476,95 @@
     }
 }
 
+- (BOOL)isPointInTitlebar:(NSPoint)windowPoint
+{
+    auto parent = _parent.tryGetWithCast<WindowImpl>();
+    if (!parent || !_isExtended) {
+        return NO;
+    }
+    
+    AvnView* view = parent->View;
+    NSPoint viewPoint = [view convertPoint:windowPoint fromView:nil];
+    double titlebarHeight = [self getExtendedTitleBarHeight];
+    
+    // Check if click is in titlebar area (top portion of view)
+    if (viewPoint.y <= titlebarHeight) {
+        // Verify we're actually in a toolbar-related area
+        NSView* hitView = [[self findRootView:view] hitTest:windowPoint];
+        if (hitView) {
+            NSString* hitViewClass = [hitView className];
+            if ([hitViewClass containsString:@"Toolbar"] || [hitViewClass containsString:@"Titlebar"]) {
+                return YES;
+            }
+        }
+    }
+    return NO;
+}
+
+- (void)forwardToAvnView:(NSEvent *)event
+{
+    auto parent = _parent.tryGetWithCast<WindowImpl>();
+    if (!parent) {
+        return;
+    }
+    
+    switch(event.type) {
+        case NSEventTypeLeftMouseDown:
+            [parent->View mouseDown:event];
+            break;
+        case NSEventTypeLeftMouseUp:
+            [parent->View mouseUp:event];
+            break;
+        case NSEventTypeLeftMouseDragged:
+            [parent->View mouseDragged:event];
+            break;
+        case NSEventTypeRightMouseDown:
+            [parent->View rightMouseDown:event];
+            break;
+        case NSEventTypeRightMouseUp:
+            [parent->View rightMouseUp:event];
+            break;
+        case NSEventTypeRightMouseDragged:
+            [parent->View rightMouseDragged:event];
+            break;
+        case NSEventTypeOtherMouseDown:
+            [parent->View otherMouseDown:event];
+            break;
+        case NSEventTypeOtherMouseUp:
+            [parent->View otherMouseUp:event];
+            break;
+        case NSEventTypeOtherMouseDragged:
+            [parent->View otherMouseDragged:event];
+            break;
+        case NSEventTypeMouseMoved:
+            [parent->View mouseMoved:event];
+            break;
+        default:
+            break;
+    }
+}
+
 - (void)sendEvent:(NSEvent *_Nonnull)event
 {
+    // Event-tracking loop for thick titlebar mouse events
+    if (event.type == NSEventTypeLeftMouseDown && [self isPointInTitlebar:event.locationInWindow])
+    {
+        NSEventMask mask = NSEventMaskLeftMouseDragged | NSEventMaskLeftMouseUp;
+        NSEvent *ev = event;
+        while (ev.type != NSEventTypeLeftMouseUp)
+        {
+            [self forwardToAvnView:ev];
+            [super sendEvent:ev]; 
+            ev = [NSApp nextEventMatchingMask:mask
+                                     untilDate:[NSDate distantFuture]
+                                        inMode:NSEventTrackingRunLoopMode
+                                       dequeue:YES];
+        }
+        [self forwardToAvnView:ev];
+        [super sendEvent:ev];
+        return;
+    }
+    
     [super sendEvent:event];
 
     auto parent = _parent.tryGetWithCast<WindowImpl>();

samples/IntegrationTestApp/Pages/WindowDecorationsPage.axaml

@@ -9,6 +9,7 @@
     <CheckBox Name="WindowForceSystemChrome" Content="Force SystemChrome" />
     <CheckBox Name="WindowPreferSystemChrome" Content="Prefer SystemChrome" />
     <CheckBox Name="WindowMacThickSystemChrome" Content="Mac Thick SystemChrome" />
+    <CheckBox Name="WindowShowTitleAreaControl" Content="Show Title Area Control" />
     <TextBox Name="WindowTitleBarHeightHint" Text="-1" Watermark="In dips" />
     <Button Name="ApplyWindowDecorations"
             Content="Apply decorations on this Window"

samples/IntegrationTestApp/Pages/WindowDecorationsPage.axaml.cs

@@ -21,6 +21,12 @@ public partial class WindowDecorationsPage : UserControl
             | (WindowForceSystemChrome.IsChecked == true ? ExtendClientAreaChromeHints.SystemChrome : 0)
             | (WindowPreferSystemChrome.IsChecked == true ? ExtendClientAreaChromeHints.PreferSystemChrome : 0)
             | (WindowMacThickSystemChrome.IsChecked == true ? ExtendClientAreaChromeHints.OSXThickTitleBar : 0);
+        
+        if (window is ShowWindowTest showWindowTest && WindowShowTitleAreaControl.IsChecked == true)
+        {
+            showWindowTest.ShowTitleAreaControl();
+        }
+        
         AdjustOffsets(window);
 
         window.Background = Brushes.Transparent;

samples/IntegrationTestApp/ShowWindowTest.axaml

@@ -5,8 +5,17 @@
         Name="SecondaryWindow"
         x:DataType="Window"
         Title="Show Window Test">
-  <integrationTestApp:MeasureBorder Name="MyBorder" Background="{DynamicResource SystemRegionBrush}">
-    <Grid ColumnDefinitions="Auto,Auto" RowDefinitions="Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto">
+  <Grid>
+    <Grid Name="TitleAreaControl" IsVisible="False" 
+          Background="LightBlue" VerticalAlignment="Top" ZIndex="100"
+          Margin="0,0,0,0">
+      <TextBlock Text="Title Area Control (Tabs)" 
+                 HorizontalAlignment="Center" VerticalAlignment="Center" 
+                 Foreground="DarkBlue" FontWeight="Bold" />
+    </Grid>
+    
+    <integrationTestApp:MeasureBorder Name="MyBorder" Background="{DynamicResource SystemRegionBrush}">
+    <Grid ColumnDefinitions="Auto,Auto" RowDefinitions="Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto,Auto">
       <Label Grid.Column="0" Grid.Row="1">Client Size</Label>
       <TextBox Name="CurrentClientSize" Grid.Column="1" Grid.Row="1" IsReadOnly="True"
                Text="{Binding ClientSize, Mode=OneWay}" />
@@ -53,12 +62,19 @@
       <Label Grid.Row="11" Content="MeasuredWith:" />
       <TextBlock Grid.Column="1" Grid.Row="11" Name="CurrentMeasuredWithText" Text="{Binding #MyBorder.MeasuredWith}" />
 
-      <StackPanel Orientation="Horizontal" Grid.Row="12">
+      <Label Grid.Column="0" Grid.Row="12">Mouse Move Event Count</Label>
+      <TextBox Name="MouseMoveCount" Grid.Column="1" Grid.Row="12" IsReadOnly="True" Text="0" />
+      
+      <Label Grid.Column="0" Grid.Row="13">Mouse Release Event Count</Label>
+      <TextBox Name="MouseReleaseCount" Grid.Column="1" Grid.Row="13" IsReadOnly="True" Text="0" />
+      
+      <StackPanel Orientation="Horizontal" Grid.Row="14" Grid.ColumnSpan="2">
         <Button Name="HideButton" Command="{Binding $parent[Window].Hide}">Hide</Button>
         <Button Name="AddToWidth" Click="AddToWidth_Click">Add to Width</Button>
         <Button Name="AddToHeight" Click="AddToHeight_Click">Add to Height</Button>
       </StackPanel>
       
     </Grid>
-  </integrationTestApp:MeasureBorder>
+    </integrationTestApp:MeasureBorder>
+  </Grid>
 </Window>

samples/IntegrationTestApp/ShowWindowTest.axaml.cs

@@ -30,6 +30,8 @@ namespace IntegrationTestApp
     {
         private readonly DispatcherTimer? _timer;
         private readonly TextBox? _orderTextBox;
+        private int _mouseMoveCount;
+        private int _mouseReleaseCount;
 
         public ShowWindowTest()
         {
@@ -37,6 +39,10 @@ namespace IntegrationTestApp
             DataContext = this;
             PositionChanged += (s, e) => CurrentPosition.Text = $"{Position}";
 
+            PointerMoved += OnPointerMoved;
+            PointerReleased += OnPointerReleased;
+            PointerExited += (_, e) => ResetCounters();
+
             if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
             {
                 _orderTextBox = CurrentOrder;
@@ -74,5 +80,47 @@ namespace IntegrationTestApp
 
         private void AddToWidth_Click(object? sender, RoutedEventArgs e) => Width = Bounds.Width + 10;
         private void AddToHeight_Click(object? sender, RoutedEventArgs e) => Height = Bounds.Height + 10;
+        
+        private void OnPointerMoved(object? sender, Avalonia.Input.PointerEventArgs e)
+        {
+            _mouseMoveCount++;
+            UpdateCounterDisplays();
+        }
+        
+        private void OnPointerReleased(object? sender, Avalonia.Input.PointerReleasedEventArgs e)
+        {
+            _mouseReleaseCount++;
+            UpdateCounterDisplays();
+        }
+        
+        public void ResetCounters()
+        {
+            _mouseMoveCount = 0;
+            _mouseReleaseCount = 0;
+            UpdateCounterDisplays();
+        }
+        
+        private void UpdateCounterDisplays()
+        {
+            var mouseMoveCountTextBox = this.FindControl<TextBox>("MouseMoveCount");
+            var mouseReleaseCountTextBox = this.FindControl<TextBox>("MouseReleaseCount");
+            
+            if (mouseMoveCountTextBox != null)
+                mouseMoveCountTextBox.Text = _mouseMoveCount.ToString();
+            
+            if (mouseReleaseCountTextBox != null)
+                mouseReleaseCountTextBox.Text = _mouseReleaseCount.ToString();
+        }
+        
+        public void ShowTitleAreaControl()
+        {
+            var titleAreaControl = this.FindControl<Grid>("TitleAreaControl");
+            if (titleAreaControl == null) return;
+            titleAreaControl.IsVisible = true;
+                
+            var titleBarHeight = ExtendClientAreaTitleBarHeightHint > 0 ? ExtendClientAreaTitleBarHeightHint : 30;
+            titleAreaControl.Margin = new Thickness(110, -titleBarHeight, 8, 0);
+            titleAreaControl.Height = titleBarHeight;
+        }
     }
 }

tests/Avalonia.IntegrationTests.Appium/PointerTests_MacOS.cs

@@ -0,0 +1,89 @@
+using System;
+using System.Threading;
+using OpenQA.Selenium.Appium;
+using OpenQA.Selenium.Interactions;
+using Xunit;
+
+namespace Avalonia.IntegrationTests.Appium;
+
+[Collection("WindowDecorations")]
+public class PointerTests_MacOS : TestBase, IDisposable
+{
+    public PointerTests_MacOS(DefaultAppFixture fixture)
+        : base(fixture, "Window Decorations")
+    {
+    }
+
+    [PlatformFact(TestPlatforms.MacOS)]
+    public void OSXThickTitleBar_Pointer_Events_Continue_Outside_Window_During_Drag()
+    {
+        // issue #15696
+        SetParameters(true, false, true, true, true);
+        
+        var showNewWindowDecorations = Session.FindElementByAccessibilityId("ShowNewWindowDecorations");
+        showNewWindowDecorations.Click();
+        
+        Thread.Sleep(1000);
+        
+        var secondaryWindow = Session.GetWindowById("SecondaryWindow");
+        
+        var titleAreaControl = secondaryWindow.FindElementByAccessibilityId("TitleAreaControl");
+        Assert.NotNull(titleAreaControl);
+
+        new Actions(Session).MoveToElement(secondaryWindow).Perform();
+        new Actions(Session).MoveToElement(titleAreaControl).Perform();
+        new Actions(Session).DragAndDropToOffset(titleAreaControl, 50, -100).Perform();
+        
+        var finalMoveCount = GetMoveCount(secondaryWindow);
+        var finalReleaseCount = GetReleaseCount(secondaryWindow);
+            
+        Assert.True(finalMoveCount >= 10, $"Expected at least 10 new mouse move events outside window, got {finalMoveCount})");
+        Assert.Equal(1, finalReleaseCount);
+        
+        secondaryWindow.FindElementByAccessibilityId("_XCUI:CloseWindow").Click();
+    }
+    
+    private void SetParameters(
+        bool extendClientArea,
+        bool forceSystemChrome,
+        bool preferSystemChrome,
+        bool macOsThickSystemChrome,
+        bool showTitleAreaControl)
+    {
+        var extendClientAreaCheckBox = Session.FindElementByAccessibilityId("WindowExtendClientAreaToDecorationsHint");
+        var forceSystemChromeCheckBox = Session.FindElementByAccessibilityId("WindowForceSystemChrome");
+        var preferSystemChromeCheckBox = Session.FindElementByAccessibilityId("WindowPreferSystemChrome");
+        var macOsThickSystemChromeCheckBox = Session.FindElementByAccessibilityId("WindowMacThickSystemChrome");
+        var showTitleAreaControlCheckBox = Session.FindElementByAccessibilityId("WindowShowTitleAreaControl");
+
+        if (extendClientAreaCheckBox.GetIsChecked() != extendClientArea)
+            extendClientAreaCheckBox.Click();
+        if (forceSystemChromeCheckBox.GetIsChecked() != forceSystemChrome)
+            forceSystemChromeCheckBox.Click();
+        if (preferSystemChromeCheckBox.GetIsChecked() != preferSystemChrome)
+            preferSystemChromeCheckBox.Click();
+        if (macOsThickSystemChromeCheckBox.GetIsChecked() != macOsThickSystemChrome)
+            macOsThickSystemChromeCheckBox.Click();
+        if (showTitleAreaControlCheckBox.GetIsChecked() != showTitleAreaControl)
+            showTitleAreaControlCheckBox.Click();
+    }
+    
+    private int GetMoveCount(AppiumWebElement window)
+    {
+        var mouseMoveCountTextBox = window.FindElementByAccessibilityId("MouseMoveCount");
+        return int.Parse(mouseMoveCountTextBox.Text ?? "0");
+    }
+    
+    private int GetReleaseCount(AppiumWebElement window)
+    {
+        var mouseReleaseCountTextBox = window.FindElementByAccessibilityId("MouseReleaseCount");
+        return int.Parse(mouseReleaseCountTextBox.Text ?? "0");
+    }
+
+    public void Dispose()
+    {
+        SetParameters(false, false, false, false, false);
+        var applyButton = Session.FindElementByAccessibilityId("ApplyWindowDecorations");
+        applyButton.Click();
+    }
+}