private void btn_Color_Click(object sender, EventArgs e)
{
DialogResult result = colorDialog1.ShowDialog();
// See if user pressed ok.
if (result == DialogResult.OK)
{
// Set form background to the selected color.
btn_Paint.BackColor = colorDialog1.Color;
pnl_ColorCoat.BackColor = colorDialog1.Color;
//this.BackColor = colorDialog1.Color;
}
}