private void button1_Click(object sender, EventArgs e)
        {
            this.Hide();
            POS open = new POS();

            open.Show();
        }
        private void btnTable1_Click(object sender, EventArgs e)
        {
            POS p1 = new POS();

            p1.MdiParent = this;
            p1.Text      = "Point Of Sale";
            p1.Show();
        }