public static LookupItemAvailability getCashierForm(int id, string branch)
        {
            if (lookUpItemAvailability == null)
            {
                lookUpItemAvailability = new LookupItemAvailability(id, branch);
            }

            return(lookUpItemAvailability);
        }
        private void button3_Click(object sender, EventArgs e)
        {
            parentButtonActivation(false);
            LookupItemAvailability availabilityForm = LookupItemAvailability.getCashierForm(logged_id, branch);

            availabilityForm.MdiParent = this;
            splitContainer1.Panel2.Controls.Add(availabilityForm);
            availabilityForm.Location        = new Point((splitContainer1.Panel2.Width - availabilityForm.Width) / 2, (splitContainer1.Panel2.Height - availabilityForm.Height) / 2);
            availabilityForm.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
            availabilityForm.Show();
            availabilityForm.buttonDeactivate();
            availabilityForm.setParentForm(this);
        }