The part of the KCM where I can configure the titlebar buttons looks very out of place when using the breeze-dark theme. Reproducible: Always
Created attachment 95803 [details] kwin decorations KCM
Should be fixed by https://git.reviewboard.kde.org/r/125393/ in 5.5 Please re-open if not. You'll have similar issues with the effects kcm, I've a 95% solution, but it makes (check)buttons in the view unreadable. QML is a bit like gtk reg. color robustness :-(
Created attachment 95986 [details] 5.5.0 look just installed 5.5.0 (gentoo). This is how it looks now. Sorry to say, still not good. Reopening...
So much for using the SystemPalette - the background *should* be SystemPalette.base and that *should* be #232629 (for breeze dark) but apparently *is* #FFFFFF - *unconditionally*. Also see https://git.reviewboard.kde.org/r/126267/ and https://git.reviewboard.kde.org/r/126270/ on why the system is broken anyway. **GRRRR***
Will be fixed with https://phabricator.kde.org/D17982
Fixed with https://phabricator.kde.org/D17982!