See the attached image. Reproducible: Always I am using the binary AMD drivers (6870 card) so you could say it's my drivers.. However, this is not happening with the QWidget based one prior to KDE 4.9.
Created attachment 72385 [details] artifacts
I do not have this problem here and the new QML dialog implementation uses the same logout effect used by the QWidget one. I use the QML dialog with KDE SC 4.8.4, when I upgrade to 4.9.0 I can test if I can reproduce this problem. However, if it starts to happen only after upgrading to 4.9.0 then the problem is somewhere else. OBS: my notebook's card is an ATI 4570 and I also use the proprietary drivers.
not reproducible here as well, it seems graphics driver related
And closed. The logout effect is working again (the one Martin blogged about) and that either hides the visual effect that i showed in the attachment or it even fixes it. Either way, it's not visible anymore thus closing.