Total DM noob here building my first map. I've searched for the answer to this but maybe my Google-Fu is weak.
When I add a rectangular Prop (for example "Free Wall" but true for all these non-square Props), the "Rotate" option is greyed out. If I press 'R' I get this message:
"The object is not square. You must move it to rotate it."
What gives? How do I rotate these things?