@ngraham my bad, didn't see your edit ^^

This doesn't fix the problem for me until I actually apply a Global Theme. Until I do that, the current widget style remaing un-highlighted in the Style KCM. It does fix the issue for that use case though.

So this is clearly a correct fix, but I'm not sure it's sufficient to fully resolve 417515.

In D27407#611723, @ngraham wrote:

This doesn't fix the problem for me until I actually apply a Global Theme. Until I do that, the current widget style remaing un-highlighted in the Style KCM. It does fix the issue for that use case though.

Yes, it requires to apply Breeze style again, to set widgetStyle to Breeze in kdeglobals, instead of breeze

Could we maybe ship a kconfig update script to change the string in the config file for people who don't ever change their global theme? Or is the problem moot because the global theme gets automatically applied on upgrade or something?

Sounds like it will provide a complete fix, the update script will fix the issue without requiring the user to reset its application style, and this patch will ensure it won't come back.

Shall we expect the migration script in that patch or another one?

Separate commit is probably fine, but if this lands on the stable branch, it should come soon.

Will do in a separate commit. I guess it's more or less related to the KCM Style.