Greg Egan on Nostr: Does anyone else with a Mac with multiple keyboard layouts defined keep seeing a ...

Does anyone else with a Mac with multiple keyboard layouts defined keep seeing a little blue menu offering them the chance to switch keyboards popping up — apparently at random, and not in response to any mouse action or key presses as far as I can tell — in all kinds of different apps, since upgrading to Sonoma?

I have no idea what triggers this, or how to switch it off, and it’s driving me crazy. Maybe I’m accidentally pressing some magic key combination in bouts of clumsy typing, but I can’t see anything in the Settings that would explain this. In Keyboard > Input Sources I’ve switched off using the Caps Lock key to “switch to and from last used Latin input source”, and there’s nothing else that seems relevant.