The absence of the Network Manager icon is a long standing issue - I’ve
tried to get some KDE developers onboard, but as yet with no success.
After a while, you just know where the icon should be from its absence.
(There are horrible hacks to make the icon appear - I think that the
screenshots I posted showed this: I don’t use them.)
I don’t use Whonix and cant see that image. If it’s weird I suspect that
the icons are not provided in scalable format. It’s an issue for Whonix.
The cascading menu doesn’t have icons - nothing is broken,that’s the
way it is.
I rarely use the q-domains menu, but nor has anyone reported this to me,
so I suspect in use it isn’t that important. I’ll see if there is an
obvious explanation.
There’s another KDE artefact - Top Right is a control field, but it gets
overlaid with a black square for each of the icons in the control
panel - disk, clipboard, devices etc. Use them once, and the square goes.