[Windows] - Resolved FlyoutBehavior "Locked" State Reset Issue After Navigation

src/Controls/src/Core/ShellToolbar.cs

@@ -90,7 +90,8 @@ internal void ApplyChanges()
 				backButtonVisible = _backButtonBehavior.IsVisible;
 			}
 
-			_drawerToggleVisible = stack.Count <= 1;
+			var flyoutBehavior = (_shell as IFlyoutView).FlyoutBehavior;
+			_drawerToggleVisible = stack.Count <= 1 && flyoutBehavior is FlyoutBehavior.Flyout;
 			BackButtonVisible = backButtonVisible && stack.Count > 1;
 			BackButtonEnabled = _backButtonBehavior?.IsEnabled ?? true;
 			ToolbarItems = _toolbarTracker.ToolbarItems;
@@ -103,7 +104,6 @@ internal void ApplyChanges()
 				if (_shell.IsSet(Shell.NavBarIsVisibleProperty))
 					return (bool)_shell.GetValue(Shell.NavBarIsVisibleProperty);
 
-				var flyoutBehavior = (_shell as IFlyoutView).FlyoutBehavior;
 #if WINDOWS
 				return (!String.IsNullOrEmpty(Title) ||
 					TitleView != null ||

src/Controls/tests/TestCases.HostApp/Issues/Issue27337.cs

@@ -0,0 +1,51 @@
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 27337, "Flyout with FlyoutBehavior='Locked' unlocks (reverts to Flyout) after navigation", PlatformAffected.UWP)]
+	public class Issue27337 : TestShell
+	{
+		protected override void Init()
+		{
+			ContentPage MainPage = new ContentPage
+			{
+				Title = "Home",
+				Content = new VerticalStackLayout
+				{
+					Children =
+					{
+						new Button
+						{
+							AutomationId = "SecondPageButton",
+							Text = "Navigate to Second Page",
+							HorizontalOptions = LayoutOptions.Fill,
+							Command = new Command(() => Shell.Current.GoToAsync("Issue27337_SecondPage"))
+						}
+					}
+				}
+			};
+
+			FlyoutBehavior = FlyoutBehavior.Locked;
+
+			Items.Add(new FlyoutItem
+			{
+				Title = "Home",
+				Items =
+				{
+					new ShellContent
+					{
+						Content = MainPage
+					}
+				}
+			});
+
+			Routing.RegisterRoute("Issue27337_SecondPage", typeof(Issue27337_SecondPage));
+		}
+	}
+
+	public class Issue27337_SecondPage : ContentPage
+	{
+		public Issue27337_SecondPage()
+		{
+			Title = "Second Page";
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue27337.cs

@@ -0,0 +1,36 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue27337 : _IssuesUITest
+	{
+		public override string Issue => "Flyout with FlyoutBehavior='Locked' unlocks (reverts to Flyout) after navigation";
+
+		public Issue27337(TestDevice device) : base(device)
+		{
+		}
+
+		[Test]
+		[Category(UITestCategories.Shell)]
+		public void EnsureFlyoutBehaviourAsLockedAfterNavigation()
+		{
+			App.WaitForElement("SecondPageButton");
+			App.Tap("SecondPageButton");
+			App.Back();
+			VerifyNoFlyoutIconAfterBackNavigation();
+		}
+
+		void VerifyNoFlyoutIconAfterBackNavigation()
+		{
+#if ANDROID
+			App.WaitForNoElement(AppiumQuery.ByXPath("//android.widget.ImageButton[@content-desc=\"Open navigation drawer\"]"));
+#elif IOS || MACCATALYST
+			App.WaitForNoElement("OK");
+#elif WINDOWS
+			App.WaitForNoElement(AppiumQuery.ByAccessibilityId("TogglePaneButton"));
+#endif
+		}
+	}
+}