internal override void KeyUp(KeyEventArgs e)
        {
            base.KeyUp(e);

            if ((e.KeyCode == Keys.Enter) && (AcceptButton != null))
            {
                AcceptButton.DoClick();
            }
            if ((e.KeyCode == Keys.Escape) && (CancelButton != null))
            {
                CancelButton.DoClick();
            }
        }