/// <summary>
/// Removes a GameScreen from the GameScreen manager. You should normally
/// use GameScreen.ExitScreen instead of calling this directly, so
/// the GameScreen can gradually transition off rather than just being
/// instantly removed.
/// </summary>
public void RemoveScreen(GameScreen GameScreen)
{
// If we have a graphics device, tell the GameScreen to unload content.
if (isInitialized) {
GameScreen.UnloadContent();
}
screens.Remove(GameScreen);
screensToUpdate.Remove(GameScreen);
}