To stack orders

You can place orders at the same side of the market, for the same price, and for the same commodity, but with different order types by creating a stacked order.

Drag and drop the orders in the same price field.  You can also use the keyboard.

Double-click the stacked order icon to see the details for individual orders.  You can also press [+] on your numeric keyboard.  Pressing [-] closes the details.