Piano roll stopped working: stuck on one instrument

Weird--- I compose and edit software instruments mostly using the Piano Roll. Now it's stuck: if I highlight instrument MIDI data, the Piano Roll shows, always, just one of the tracks' data--- and the same one--- I switch instruments, but the Piano Roll always now shows data from just one of my tracks, and the same one. It's like it's stuck displaying data from only this one, single track. I highlight other tracks, but the Piano Roll only shows the same data, from the other, different track.

When I click/highlight/select the instrument recorded-data area for editing, on the left it shows the correct instrument--- "Tweed electric guitar" for example--- then also it says "No regions selected."

I'm a primitive and never had any need for Regions--- I looked around trying to see how/where to select the "region" rather than the raw MIDI data area, which is how I've done it for the past 8 years--- still, nothing seems to work.

I note the Score and Step Editor "see" correctly the instrument data I want to edit; only the Piano Roll is now stuck, it sees only that one lonely instrument data field--- from a different track.

I don't think I hit anything or changed settings. I think Logic just made a settings-jump on me, it wants to force me to learn more about Regions or something, ha ha... I've attached a brief video showing how the Score and Step Editor "see" the correct data--- but the Piano Roll does not.

Hoping someone has a quick-and-easy solution.

15-inch MB pro, 8 gb Ram, 2.3 ghz Intel i7

Mojave 10.14.6