New problem with "Command Not Allowed..." popup in Logic

Using Logic 11.0.1 on a Mac Mini running Sonoma 14.5. My first time using Logic since the most recent update. This is a problem I've never encountered in years of using Logic.

I'm entering MIDI notes using a keyboard and editing in Piano Roll. I go into the Signature List because I want to add a bar of 2/4. Once I exit the Signature List, I can no longer play or really do much of anything else. I can edit note lengths, and some other things (MIDI still works) but no playback or record functions. Also much of the menus are now greyed out - I can't get back to the Signature List. If I hit ESCAPE, the screen flashes. I sometimes get a "Command not allowed because ..." something about Focus. If I close the project and re-open it, the problem persists. I have to quit Logic and restart. The only other app running is Safari. I check for other windows open, but nothing.