[QUESTION] "bed has already been placed here"

I'm having a weird glitch in my isolation ward. When I'm trying to move or add beds, it keeps telling me that a bed "has already been placed here", but there's nothing there. I've tried bulldozing the area, removing the room and recreating it, and quitting and reloading, but I still get the same message. Any thoughts?

Hi, thanks for the message! A quick guess: is the area one big room? Only one bed is allowed in each isolation room, so you might need to split the room markings in management.

Yep, that did it. It didn't occur to me that I had to isolate the room BEFORE I could even put a bed in it. I'm still having some confusion about how to tell when a bed is considered fully isolated, but it's working now. Thanks!