When parent window cannot be found the paired snackbar is still available. This can occur if the Snackbar is hosted outside of a WPF Window such as in a WinForms application.

Fixes #946

Author: Keboo

MaterialDesignThemes.Wpf/SnackbarMessageQueue.cs

@@ -328,7 +328,7 @@ private DispatcherOperation<Snackbar> FindSnackbar(Dispatcher dispatcher)
                 {
                     if (!sb.IsLoaded || sb.Visibility != Visibility.Visible) return false;
                     var window = Window.GetWindow(sb);
-                    return window != null && window.WindowState != WindowState.Minimized;
+                    return window?.WindowState != WindowState.Minimized;
                 });
             });
         }