I have checked every wall on my structure and none of them have "No Room Definition" selected. All of my walls seem to be completely enclosed. My Room Layer Display is unlocked. Is there something else I should look into? As you can see in the screenshot, whenever I try to select a room, the Slab Specification window pops up. I am unable to select a room in any part of my structure. Hoping there is a simple fix for this! Thanks so much for any help you can offer!