public void ShowSettingsWindow()
 {
     if (window == null)
     {
         window         = new NotificationSettingsWindow();
         window.Closed += window_Closed;
         Controller.ShowWindow(window);
     }
     else
     {
         window.Focus();
     }
 }
 void window_Closed(object sender, EventArgs e)
 {
     window.Closed -= window_Closed;
     window = null;
 }
 public void ShowSettingsWindow()
 {
     if (window == null)
     {
         window = new NotificationSettingsWindow();
         window.Closed += window_Closed;
         Controller.ShowWindow(window);
     }
     else
     {
         window.Focus();
     }
 }
 void window_Closed(object sender, EventArgs e)
 {
     window.Closed -= window_Closed;
     window         = null;
 }