I think the title says it all but if needed - I’ll edit this. Of course I googled but I got nowhere. Google results were total shit. Google won’t help me if I don’t know the exact name for that fucking thing. It’s a very stupid design choice. Five regular old push buttons would be so much better.
About an hour ago I managed to stick it back on but I’m nearly 100% sure it’s going to fall off again in week or two if not far sooner.
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Edit
I don’t mean part of the unit itself. I mean just the thin plastic cover over the buttons that’s ~3mm thick.
You can probably glue it back on with some super glue. Just a little on the edges of the rubbery cover should do it.
If you want something less permanent just slap some clear packing tape over it. You’ll still have enough “give” in the tape to push the buttons and since it’s clear you can read what’s under the tape. Then if you want to try a bigger fix later you can remove the tape.