Bug 355416

It's been a while, but I decided to change my KDE4 desktop style to a hopefully less graphics-intensive theme (QtCurve instead of Oxygen).

The change got recorded in ~/.kde/share/config/kdeglobals and showed up in style kcm, was reflected in running applications, but not in newly started applications. That includes systemsettings, which would show QtCurve as the selected style in the combobox, but use Oxygen as the running style.
I had to "confirm" the change via qtconfig to get it to "stick".

./kdeui/kernel/kglobalsettings.cpp

Reproducible: Always

Steps to Reproduce:
1. Start systemsettings and select new app style in the application style kcontrol
2. apply it
3. observe running applications changing  their look
4. restart systemsettings

Actual Results:  
Systemsettings will use the previous app style

Expected Results:  
Systemsettings and other newly (re)started apps use the newly selected app style

I remember that getting a non-standard default font to "stick" required configuring it via qtconfig too but AFAICR this was not the case with application styles. I think I can even remember discovering that one had to set the same style via qtconfig or else "pure" Qt applications would not use the style selected for KDE apps.

I had a look at git blame ./kdeui/kernel/kglobalsettings.cpp, and saw that the whole file was changed in july 2014 . That's maybe after I last tried to change my desktop app style but it doesn't help understanding why KDE no longer overrides the Qt style (or if it indeed ever did).