Fixes #3918 and #3913 - Accepting behavior (#3921)

* Fixed #3905, #3918

* Tweaked Generic

* Label code cleanup

* Clean up.

* Clean up.

* Clean up2.

NativeAot/Program.cs

@@ -105,6 +105,8 @@ public class ExampleWindow : Window
             {
                 MessageBox.ErrorQuery ("Logging In", "Incorrect username or password", "Ok");
             }
+            // Anytime Accepting is handled, make sure to set e.Cancel to false.
+            e.Cancel = false;
         };
 
         // Add the views to the Window