fix: The parent of FrameworkElement is always null in GenerateBitmap

src/SamplesApp/SamplesApp.UnitTests.Shared/Controls/UITests/Presentation/SampleChooserViewModel.cs

@@ -74,6 +74,7 @@ public partial class SampleChooserViewModel
 
 		private Section _lastSection = Section.Library;
 		private readonly Stack<Section> _previousSections = new Stack<Section>();
+		private bool _isRecordAllTests = false;
 
 		// A static instance used during UI Testing automation
 		public static SampleChooserViewModel Instance { get; private set; }
@@ -267,6 +268,7 @@ internal async Task RecordAllTests(CancellationToken ct, string screenShotPath =
 		{
 			try
 			{
+				_isRecordAllTests = true;
 				IsSplitVisible = false;
 
 				var folderName = Path.Combine(screenShotPath, "UITests-" + DateTime.Now.ToString("yyyyMMdd-hhmmssfff", CultureInfo.InvariantCulture));
@@ -277,7 +279,12 @@ await Window.Current.Dispatcher.RunAsync(
 					CoreDispatcherPriority.Normal,
 					async () =>
 					{
-						await RecordAllTestsInner(folderName, ct, doneAction);
+						try {
+						  await RecordAllTestsInner(folderName, ct, doneAction);
+						}
+						finally {
+						  _isRecordAllTests = false;
+						}
 					});
 			}
 			catch (Exception e)
@@ -467,6 +474,10 @@ private void ObserveChanges()
 
 				void Update(SampleChooserContent newContent)
 				{
+					if (_isRecordAllTests)
+					{
+						return;
+					}
 					var unused = Window.Current.Dispatcher.RunAsync(
 						CoreDispatcherPriority.Normal,
 						async () =>