private void tsbRefundList_Click(object sender, EventArgs e)
 {
     if (_refundlist == null || _refundlist.IsDisposed == true)
     {
         _refundlist = new frmRefundList();
         _refundlist.Show();
     }
     _refundlist.BringToFront();
 }
        private void llRefundList_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            frmRefundList frm = new frmRefundList();

            frm.Show();
        }