private void button5_Click(object sender, EventArgs e)  //Beverage add button
 {
     if (Box_beverages.SelectedIndex != -1)
     {
         order.beverages.Add(new Beverage((string)Box_beverages.SelectedItem));
         updateOrderBox();
         Box_beverages.ClearSelected();
     }
 }
 private void button8_Click(object sender, EventArgs e)  //add pizza button
 {
     //currentPizza++;
     //button8.Enabled = false;
     Box_crust.Enabled     = false;
     Box_beverages.Enabled = true;
     Box_toppings.Enabled  = false;
     Box_size.Enabled      = true;
     Box_crust.ClearSelected();
     Box_beverages.ClearSelected();
     Box_toppings.ClearSelected();
 }