"Invisible" menu text in MuseScore's Dark Theme (Windows)
This is actually an old version 3.X bug, so there's probably already an issue about it that I just haven't found. Since I haven't used the dark theme for a long time, I didn't pursue the bug further.
select the dark theme under preferences–general
if MuseScore stays open, and you do a suspend/hibernation of Windows, then the menu and menu text are both grayed out, making it impossible to read the entries (File... etc.):
Workaround: switch to light theme and back again to dark theme or restart MuseScore