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    class HighlightButton : Button
    {
        public Color HighlightBackColor {get; set;}
        private Color oldBackColor;

        protected override void OnGotFocus(EventArgs e)
        {
            oldBackColor = this.BackColor;
            this.BackColor = highlightBackColor;
            base.OnGotFocus(e);
        }

        protected override void OnLostFocus(EventArgs e)
        {
            this.BackColor = oldBackColor;
            base.OnLostFocus(e);
        }
    }