1        protected override CreateParams CreateParams
2        {
3            get
4            {
5                CreateParams cp = base.CreateParams;
6                cp.ExStyle |= 0x20;
7                return cp;
8            }
9        }
10
11public constructor()
12{
13            this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
14            this.SetStyle(ControlStyles.Opaque, true);
15}

c & p