If you want to create a locked door that can't be opened (is not supposed to be opened at all) You run into some unnecessary choices and mouse clicking that I believe could be avoided.
When I create the <object> door and want to set up the properties things begin to get cumbersome.
I can't choose to have the door locked unless I tick the box Object can be opened and closed. Then I can choose the door to be locked but not unless I provide a key to unlocking it.
Isn't it possible to make it a bit simpler?
If you never intend on allowing the door to be unlocked, I would probably just add a text override to the response when you try to unlock it. The unlock functionality is an extension of the open/close functionality.