private void radButton2_Click_1(object sender, EventArgs e)
        {
            if (Application.OpenForms["managePayments"] == null)
            {
                if (Application.OpenForms["Invoice"] == null)
                {
                    managePayments mp = new managePayments();
                    mp.MdiParent = DHNAULA.ActiveForm;
                    mp.Size = new System.Drawing.Size(1100, 670);
                    mp.Location = new System.Drawing.Point(5, 5);
                    mp.Show();
                    this.Close();
                }

            }
        }
 private void radButton2_Click(object sender, EventArgs e)
 {
     managePayments mgp = new managePayments();
     mgp.Show();
 }
 private void radButton2_Click_1(object sender, EventArgs e)
 {
     if (Application.OpenForms["managePayments"] == null)
     {
         managePayments mp = new managePayments();
         mp.MdiParent = this;
         mp.Size = new System.Drawing.Size(820, 400);
         mp.Location = new System.Drawing.Point(330, 50);
         mp.Show();
     }
 }