Change child forms color according to MDI form's colordialog

      
        Color clr;
        private void toolStripButton1_Click(object sender, EventArgs e)
        {
            ColorDialog clDg = new ColorDialog();
            if (clDg.ShowDialog() == DialogResult.OK)
            {               
                clr = clDg.Color;
            }
                      
            foreach (Control ctl in this.Controls)
            {
                if (ctl is MdiClient)
                {
                    ctl.BackColor = clr;
                }
            }
           
        }

        private void Form1_MdiChildActivate(object sender, EventArgs e)
        {
            foreach (Form form in Application.OpenForms)
            {
                form.BackColor = clr;
            }
        }