/// <summary>
        /// On un-hightlight timer
        /// </summary>
        /// <param name="sender">sender of the event</param>
        /// <param name="e">even argument</param>
        private void OnUnhighlightTimer(object sender, EventArgs e)
        {
            int buttonIndex = _titleRenderer.TitleBarButtonIndexUnderMouse;

            if (buttonIndex >= 0)
            {
                Point mousePos = TitleBar.PointToClient(Control.MousePosition);

                _titleRenderer.UpdateTitleBarButtonIndexUnderMouse(mousePos);

                if (_titleRenderer.TitleBarButtonIndexUnderMouse != buttonIndex)
                {
                    TitleBar.Invalidate();
                }
            }
        }