diff --git a/Ink Canvas/Windows/YesOrNoNotificationWindow.xaml.cs b/Ink Canvas/Windows/YesOrNoNotificationWindow.xaml.cs
index 23e76ed4..3ee15f2c 100644
--- a/Ink Canvas/Windows/YesOrNoNotificationWindow.xaml.cs	
+++ b/Ink Canvas/Windows/YesOrNoNotificationWindow.xaml.cs	
@@ -48,7 +48,7 @@ namespace Ink_Canvas
         }
 
         private void Window_Closed(object sender, EventArgs e) {
-            _windowClose.Invoke();
+            _windowClose?.Invoke();
         }
     }
 }
\ No newline at end of file