private void button2_Click(object sender, EventArgs e)
        {
            CrePrivCusControl cpcc = new CrePrivCusControl();

            cpcc.Dock = DockStyle.Fill;
            BookingSystemForm.Instance.PnlContainer.Controls.Add(cpcc);
            cpcc.SetCustomerId(customer_id);
            BookingSystemForm.Instance.PnlContainer.Controls["CrePrivCusControl"].BringToFront();
        }
 private void button1_Click(object sender, EventArgs e)
 {
     if (!BookingSystemForm.Instance.PnlContainer.Controls.ContainsKey("CrePrivCusControl"))
     {
         CrePrivCusControl cpcc = new CrePrivCusControl();
         cpcc.Dock = DockStyle.Fill;
         BookingSystemForm.Instance.PnlContainer.Controls.Add(cpcc);
     }
     BookingSystemForm.Instance.PnlContainer.Controls["CrePrivCusControl"].BringToFront();
     BookingSystemForm.Instance.BackPic.Visible = true;
 }