private void grouperOptions_CustomPaint(PaintEventArgs e)
{
var pen = new Pen(SystemColors.ActiveBorder, 1);
e.Graphics.DrawRectangle(pen,
cboReceivedMode.Location.X - 1,
cboReceivedMode.Location.Y - 1,
cboReceivedMode.Size.Width + 1,
cboReceivedMode.Size.Height + 1);
}