Plasma system tray icons missing

After upgrade (new install, but home directory taken from prior Leap 42.2 installation) to Leap 42.3 I miss some icons in the KDE Plasma system tray. The Amarok or Akregator icon isn’t shown in the system tray:

I found older threads in the forum with the same problem but no solution.

Maybe install another Icon Theme?

Or install the Software once more?

I am seeing both Amarok and Akregator icons in the tray.

This was a clean install, including home directory. So I don’t have any settings files left over from 42.2.

As I recall, the Akregator icon shows up in the hidden tray, unless there is at least one unread article – but you can change that with system tray settings.

Try to remove the Plasma desktop theme cache:

rm -r ~/.cache/plasma*

and/or try to select a different desktop (not icon!) theme.

Thank you, that helps. So the problem was caused by the cache files left from a prior Plasma version.