[Windows] Fixed BackButton visibility issue when switching tabs without NavigationPage

src/Controls/src/Core/Platform/Windows/Extensions/ToolbarExtensions.cs

@@ -13,6 +13,7 @@ internal static class ToolbarExtensions
 		public static void UpdateIsVisible(this MauiToolbar platformToolbar, Toolbar toolbar)
 		{
 			platformToolbar.Visibility = (toolbar.IsVisible) ? UI.Xaml.Visibility.Visible : UI.Xaml.Visibility.Collapsed;
+			UpdateBackButtonVisibility(platformToolbar, toolbar);
 		}
 
 		public static void UpdateTitleIcon(this MauiToolbar platformToolbar, Toolbar toolbar)
@@ -35,8 +36,7 @@ public static void UpdateBackButton(this MauiToolbar platformToolbar, Toolbar to
 			platformToolbar.IsBackEnabled =
 				toolbar.BackButtonEnabled && toolbar.BackButtonVisible;
 
-			platformToolbar
-				.IsBackButtonVisible = (toolbar.BackButtonVisible) ? NavigationViewBackButtonVisible.Visible : NavigationViewBackButtonVisible.Collapsed;
+			UpdateBackButtonVisibility(platformToolbar, toolbar);
 
 			toolbar.Handler?.UpdateValue(nameof(Toolbar.BarBackground));
 		}
@@ -84,5 +84,13 @@ public static void UpdateToolbarDynamicOverflowEnabled(this MauiToolbar platform
 
 			platformToolbar.CommandBar.IsDynamicOverflowEnabled = toolbar.DynamicOverflowEnabled;
 		}
+
+		private static void UpdateBackButtonVisibility(MauiToolbar platformToolbar, Toolbar toolbar)
+		{
+			platformToolbar.IsBackButtonVisible = 
+				toolbar.BackButtonVisible 
+					? NavigationViewBackButtonVisible.Visible 
+					: NavigationViewBackButtonVisible.Collapsed;
+		}
 	}
 }

src/Controls/tests/TestCases.HostApp/Issues/Issue14689.cs

@@ -0,0 +1,23 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 14689, "TabbedPage Back button not updated", PlatformAffected.UWP, NavigationBehavior.SetApplicationRoot)]
+public class Issue14689 : TabbedPage
+{
+	public Issue14689()
+	{
+		Children.Add(new ContentPage() { Title = "NoNavigationPage" });
+		Children.Add(new NavigationPage(new Issue14689Page()) { Title = "HasNavigationPage" });
+		Children.Add(new NavigationPage(new Issue14689Page()) { Title = "HasNavigationPage1" });
+	}
+}
+
+public class Issue14689Page : ContentPage
+{
+	public Issue14689Page()
+	{
+		var button = new Button() { Text = "Push a page", VerticalOptions = LayoutOptions.Start, AutomationId = "button" };
+		button.Clicked += (s, e) => { this.Navigation.PushAsync(new Issue14689Page()); };
+		Content = button;
+	}
+}
+

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue14689.cs

@@ -0,0 +1,28 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue14689 : _IssuesUITest
+{
+	public Issue14689(TestDevice testDevice) : base(testDevice)
+	{
+	}
+	public override string Issue => "TabbedPage Back button not updated";
+
+	[Test]
+	[Category(UITestCategories.TabbedPage)]
+	public void TabbedPageBackButtonUpdated()
+	{
+		App.TapTab("HasNavigationPage");
+		App.WaitForElement("button");
+		App.Tap("button");
+		App.TapTab("NoNavigationPage");
+#if WINDOWS
+		VerifyScreenshot(includeTitleBar: true); // On Windows, the back button is visible in the title bar
+#else
+		VerifyScreenshot();
+#endif
+	}
+}