since I've not updated my system since some weeks, I thought it would be
a good time to do so - with two results:
1. My desktop theme changed.
2. The menu icons have gone.
Well, while the first is not a real problem (I should be able to find an
appropriate icon theme, but I'll look for that later), I don't know why
the menu icons have gone, so I don't know where to start searching for a
solution. I even didn't find something related when search the internet. :-/
However, I found two sub-folders in /usr/share/icons/Adwaita for gtk-2.0
and gtk-3.0, but only the first one contains any assets - maybe that's
the problem? Any idea?