g.FillPolygon(brush, new Point[3]
{
new Point(point.X - ComboBox.FlatComboAdapter.Offset2Pixels, point.Y - 1),
new Point(point.X + ComboBox.FlatComboAdapter.Offset2Pixels + 1, point.Y - 1),
new Point(point.X, point.Y + ComboBox.FlatComboAdapter.Offset2Pixels)
});