public static void RemoveScreen(Screen Screen)
 {
     if (Screen.ContentLoaded)
     {
         Screen.UnloadContent();
     }
     Screens.Remove(Screen);
 }
 public static void AddScreen(Screen Screen)
 {
     Screens.Add(Screen);
     if (!Screen.ContentLoaded)
     {
         Screen.Initialize();
     }
     if (!Screen.ContentLoaded)
     {
         Screen.LoadContent();
     }
 }