Fix: Fixed an issue where the title bar drag region was sometimes missing (#16549)

Author: XTorLukas

src/Files.App/UserControls/TabBar/TabBar.xaml

@@ -260,7 +260,8 @@
 						Grid.ColumnSpan="2"
 						HorizontalAlignment="Stretch"
 						VerticalAlignment="Stretch"
-						Fill="Transparent" />
+						Fill="Transparent"
+						Loaded="DragAreaRectangle_Loaded" />
 
 				</Grid>
 			</TabView.TabStripFooter>

src/Files.App/UserControls/TabBar/TabBar.xaml.cs

@@ -64,15 +64,6 @@ public TabBar()
 			tabHoverTimer.Interval = TimeSpan.FromMilliseconds(Constants.DragAndDrop.HoverToOpenTimespan);
 			tabHoverTimer.Tick += TabHoverSelected;
 
-			var appWindow = MainWindow.Instance.AppWindow;
-
-			double rightPaddingColumnWidth =
-				FilePropertiesHelpers.FlowDirectionSettingIsRightToLeft
-					? appWindow.TitleBar.LeftInset
-					: appWindow.TitleBar.RightInset;
-
-			RightPaddingColumn.Width = new(rightPaddingColumnWidth >= 0 ? rightPaddingColumnWidth : 0);
-
 			AppearanceSettingsService.PropertyChanged += (s, e) =>
 			{
 				switch (e.PropertyName)
@@ -366,5 +357,16 @@ private void TabViewItem_Loaded(object sender, RoutedEventArgs e)
 				});
 			}
 		}
+
+		private void DragAreaRectangle_Loaded(object sender, RoutedEventArgs e)
+		{
+			double scaleAdjustment = DragAreaRectangle.XamlRoot.RasterizationScale;
+			double titleBarInset = ((FilePropertiesHelpers.FlowDirectionSettingIsRightToLeft
+				? MainWindow.Instance.AppWindow.TitleBar.LeftInset
+				: MainWindow.Instance.AppWindow.TitleBar.RightInset) / scaleAdjustment) + 40;
+
+			HorizontalTabView.Measure(new(HorizontalTabView.ActualWidth - TabBarAddNewTabButton.Width - titleBarInset, HorizontalTabView.ActualHeight));
+			RightPaddingColumn.Width = new(titleBarInset >= 0 ? titleBarInset : 0);
+		}
 	}
-}
+}

src/Files.App/Views/MainPage.xaml.cs

@@ -487,4 +487,4 @@ private void PaneSplitter_ManipulationStarted(object sender, ManipulationStarted
 				InputSystemCursorShape.SizeWestEast : InputSystemCursorShape.SizeNorthSouth));
 		}
 	}
-}
+}