I much prefer Oxygen icons. Swithed to Oxygen theme in KDE Plasma 5.5.0. In desktop, some programs do not use default icons (like /\ for VLC ), but use Breeze icons. Reproducible: Always Steps to Reproduce: 1. Install fresh KDE Plasma 5.5.0. 2. Select Oxygen icons as default Actual Results: Desktop, programs menu show some Breeze theme icons. E.g. some rectangle (|>|) for VLC, instead of /\. I searched for icons and found, that used icons only exist in /usr/share/icons/breeze/apps/ Expected Results: KDE use default icons, like from /usr/share/pixmaps or /usr/share/icons/hicolor/ KDE Plasma 5.4 showed icons more correctly, so consider this as regression. Nothing help, nor deleting ~/.cache content, nor /tmp/*, nor /var/tmp/* . Seems like Breeze icons is somehow hardcoded. But for Oxygen, I suggest to use hicolor theme as premier fallback theme, not Breeze.
Created attachment 95946 [details] Desktop with Oxygen icons + some Breeze
Created attachment 95947 [details] A bit better situation was in KDE Plasma 5.4 (less Breeze icons)
It's not only Oxygen, it seems that _any_ non breeze icon theme now has part breeze icons shown. I reported the bug here: https://bugs.kde.org/show_bug.cgi?id=356064 a few days ago. A quick and dirty bodge that I've employed is to delete _all_ of the icons from the breeze icon set ( /usr/share/icons/breeze ) thus forcing any attempt to use them to revert to the fallback "inherits=" set in the (breeze) "index.theme"... ;)
@Paul Yes, I see *** This bug has been marked as a duplicate of bug 356064 ***