I decided to let her in again to see if she'd be good and let me work. She likes sitting in boxes, so I moved an empty box I had next to my reading chair and brought it close to my work chair. She entered the room and went straight for my desk. I introduced her to the box, which she sat in for a moment or two, grooming herself and liking it immensely. Then she jumped out and settled elsewhere.
Meanwhile our other cat decided HE liked the box, and sat there for a while.
All that silence got me antsy, so I looked for the first cat. Guess where she was sitting? On the floor by my reading chair, where the box used to be! Crazy kitty.