Fixed NavigationPage TitleBar visibility issue when set to the parent page

src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs

@@ -1607,7 +1607,19 @@ void UpdateNavigationBarVisibility(bool animated)
 				if (current == null || NavigationController == null)
 					return;
 
-				var hasNavBar = NavigationPage.GetHasNavigationBar(current);
+				bool hasNavBar;
+
+				if (current.Parent is not null)
+				{
+					hasNavBar = NavigationPage.GetHasNavigationBar(current.Parent)
+								&& NavigationPage.GetHasNavigationBar(current);
+				}
+				else
+				{
+					hasNavBar = NavigationPage.GetHasNavigationBar(current);
+				}
+
+
 				if (!_navigation.TryGetTarget(out NavigationRenderer navigationRenderer))
 				{
 					navigationRenderer._hasNavigationBar = hasNavBar;

src/Controls/src/Core/NavigationPage/NavigationPageToolbar.cs

@@ -218,7 +218,18 @@ void ApplyChanges(NavigationPage navigationPage)
 				previousPage = stack[stack.Count - 1];
 
 			ToolbarItems = _toolbarTracker.ToolbarItems;
-			IsVisible = NavigationPage.GetHasNavigationBar(currentPage) && _hasAppeared;
+
+			if (currentPage.Parent is not null)
+			{
+				IsVisible = NavigationPage.GetHasNavigationBar(currentPage.Parent)
+							&& NavigationPage.GetHasNavigationBar(currentPage)
+							&& _hasAppeared;
+			}
+			else
+			{
+				IsVisible = NavigationPage.GetHasNavigationBar(currentPage) && _hasAppeared;
+			}
+
 
 			UpdateBackButton();
 

src/Controls/tests/TestCases.HostApp/Issues/Issue13807.xaml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<TabbedPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.Issue13807">
+
+  <NavigationPage Title="Navigation Page"
+                HasNavigationBar="False" BarBackgroundColor="Red" BarBackground="Green">
+    <x:Arguments>
+      <ContentPage Title="Content Page">
+        <ScrollView>
+          <VerticalStackLayout Padding="30,0" Spacing="25">
+            <Label AutomationId="label" Text="Hello, World!"/>
+          </VerticalStackLayout>
+        </ScrollView>
+      </ContentPage>
+    </x:Arguments>
+  </NavigationPage>
+
+</TabbedPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue13807.xaml.cs

@@ -0,0 +1,12 @@
+namespace Maui.Controls.Sample.Issues
+{
+	[XamlCompilation(XamlCompilationOptions.Compile)]
+	[Issue(IssueTracker.Github, 13807, "NavigationPage TitleBar Persists if child pages have a title", PlatformAffected.All)]
+	public partial class Issue13807 : TabbedPage
+    {
+        public Issue13807()
+        {
+            InitializeComponent();
+        }
+    }
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue13807.cs

@@ -0,0 +1,25 @@
+#if !MACCATALYST
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+    public class Issue13807 : _IssuesUITest
+	{
+		public Issue13807(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "NavigationPage TitleBar Persists if child pages have a title";
+
+		[Test]
+		[Category(UITestCategories.Navigation)]
+		public void NavigationBarVisibility()
+		{
+			App.WaitForElement("label");
+			VerifyScreenshot();
+		}
+	}
+}
+#endif