I just installed gtk-qt-engine for the first time.
The initial settings for "GTK Styles" in KDE Control Center had both the "Use my
KDE style" and "Use another style" radio buttons unchecked. (GTK Fonts was fine
- "Use my KDE fonts" was checked by default).
After saving any changes (even without checking a value for either GTK Styles
combobox), the problem disappears.
Shouldn't one of the "GTK Styles" radio buttons be selected by default out of
the box? "Use my KDE style" could be a good choice for consistency with the
"GTK Fonts" default.
This is F8 x86_64, all updates installed.
Use GTK styles by default is unwise at this time, blockers include
1. It (sometimes) doesn't work all that well, due mostly to exposing bugs in apps/themes. unfortunately, rarely gets fixed, blame ends on gtk-qt-engine
2. implementation currently relies on an environment variable set, which requires user to logout/login anyway.
I don't see either of these being resolved any time soon.
In the meantime, I'll raise these issues upstream, see what they have to say.