Create an open corner unit by removing the shutters
Place a standard corner unit, remove its shutters to make it open, and save the result for reuse.
To make an open corner unit, place a standard corner unit and remove its shutters: select the shutter system and use the remove-shutter option.
The resulting open unit can be saved for reuse by going to the construction tab, choosing publish to catalog and adding it as new furniture.
The publish option is available from the design.