c# winfrom between two panels

private void panel1_MouseClick(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Right)
            {
                ColorDialog cd = new ColorDialog();
                if (cd.ShowDialog() == DialogResult.OK)
                {
                    this.panel3.BackColor = cd.Color;
                }
            }
        }

private void panel1_MouseDown(object sender, MouseEventArgs e)
        {
            Panel pnl = sender as Panel;
            if (pnl != null)
                pnl.DoDragDrop(pnl.BackColor, DragDropEffects.Move);
        }

        private void panel2_DragDrop(object sender, DragEventArgs e)
        {
            var data = e.Data.GetData(typeof(Color));

            if (data != null)
                ((Panel)sender).BackColor = (Color)data;
        }

        private void panel2_DragEnter(object sender, DragEventArgs e)
        {
            e.Effect = DragDropEffects.Move;
        }