Drawing on[/underneath!] Controls

Is it possible to draw a line as shown in the pic on a single form The line in the image is drawn on a second form which is transparent so form1 is visible.

So why does my line control cover the listbox

class Line : Control
{
 Pen _Pen;

 Line()
 {
   this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
   this.BackColor = Color.Transparent; 
 }

 public void SetBounds(int Width)
 {
   _Pen = new Pen(new SolidBrush(Color.Red));
   _Pen.Width = Width;
   this.Location = new Point(0, 0);
   this.Height = Form1.ClientRectangle.Height;
   this.Width = Form1.ClientRectangle.Width;
   Invalidate();
 }

 protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
 {
   base.OnPaint(e);
   _Pen.DashCap = DashCap.Flat;
   _Pen.DashStyle = DashStyle.DashDotDot;
   _Pen.StartCap = LineCap.Flat;
   _Pen.EndCap = LineCap.ArrowAnchor;
   Graphics g = this.CreateGraphics;
   g.DrawBezier(_Pen, 20, 20, 500, 300, 550, 320, 510, 60);
 }
}