@overseer:
Using FireFox 134.0.2 (64-bit), openSuSE Tumbleweed.
it's KDE counterpart Konqueror has the same issues.
Neither enabling incogito or disabling Adblock has any results.
At a given time the expanded menu is collapsed (automatically), and then it isn't useable anymore until F5 or the dashboard is clicked.
I'll try a TizenOS based browser, see if that does the trick.