Comment # 3 on bug 920792 from Wolfgang Bauer

(In reply to ��kos Sz��ts from comment #2)
> I did the vendor change and also manually checked the versions of all the
> packages to be from the right repo. Basically, there were no changes (except
> for a small deprecated QNetworkmanager5 -> 6 change).

That doesn't sound relevant.

> Later I found the qt5ct program (from package libqt5-qtct) with which I
> could configure that all the Qt 5 programs should use the Breeze theme
> (instead of the previously selected Fusion) and the Breeze icon theme (while
> nothing was selected before). Now it is really much better now. I see icons
> and Breeze theme almost everywhere.

Ok, so you changed Qt5's settings to use Breeze instead of Fusion. Shouldn't be
necessary, and will not help with other Plasma5 settings I suppose.

> Could you please tell me where can I find these Qt platform libraries to
> make sure that I have them installed correctly? I tried to search them but
> with little luck.

Sorry I forgot to mention this: it is libKF5Style5, and it has to be compiled
against the exact Qt5 version you are using. I.e. if you installed libKF5Style5
from KDE:Frameworks5, you need Qt5 from KDE:Qt5.

Btw, Qt5 detects the KDE session via the environment variable
$XDG_CURRENT_DESKTOP. Is this set? And to what? (should be "KDE")
echo $XDG_CURRENT_DESKTOP

> About the Oxygen window decoration: for me the blue window borders are too
> harsh, that's why I'm changing back to KDE 4's KWin simply by executing
> "kwin_gles --replace" after the login. Apparently, KWin5 and KWin4 are
> co-installable.

Yes they are. But you should be able to configure the window borders to your
likings in systemsettings5->Colors too.

Oh, and the window borders shouldn't be blue at all with the openSUSE color
scheme, not to mention that the Breeze window decoration doesn't even have any
(colored) window borders... ;) (as mentioned, Oxygen is not available for kwin5
at the moment)

A side-note: here is a forum thread about apparently the same problem:
https://forums.opensuse.org/showthread.php/505494-opensuse-13-2-kde5-quot-no-icons-in-Application-launcher-and-sistem-settings-quot?p=2696395#post2696395
Unfortunately we didn't find the cause, it just started working suddenly...