(In reply to comment #98)
> After some playing around, I do see some (minor) visual issues. See
> https://imgur.com/a/uswfc for some screenshots and descriptions.

Ignore this, this was most likely a layer 8 problem. I just noticed, that the
"Compositing type" for KDE's desktop effects has been XRender instead of
"OpenGL 3.1" (not sure how that changed back; maybe I had to do it for fglrx
and don't remember). Now that I've changed that, all title bars are rendered
correctly. XRender never worked with GLAMOR since I've started using GLAMOR
(IIRC it was something close to 0.3).