Reset All Preferences to Default removes essential keyboard shortcuts; fixed on restart
S4 - Minor
To reproduce, open MuseScore's Preferences and click the "Reset All Preferences to Default" button. Result: essential keyboard shortcuts are removed. By "essential shortcuts," I mean things like Close, Save, and Undo. I noticed this once before but couldn't figure out what has caused it: https://musescore.org/en/node/50486#comment-238896 Now I figured it out… and now I think I have to do another factory reset, because I'm not sure of all the shortcuts that are missing.
I'm pretty sure this was already reported, although I can't find the report; mnaybe it was a forum post. Anyhow, the effect is only temporary, it's fixed on restart. Probably we should just dcoument that a restart may be required.
Ah yes, restarting does fix it.
FWIW, my recollection of my initial investigation back when this was first reported is that the affected shortcuts are the ones not in fact defined by MuseScore at all but are provided as OS defaults by Qt. Which is to say, we have no special knowledge of or control over them. That's not to say there isn't a way of solving the problem, just that this was the wall I hit.
See also #235406: Regression: essential keyboard shortcuts missing.