Version: unspecified (using Devel)
With blur active on my Dell Mini 10v, plasma notifications, tooltips and slide-out windows now have a sexy blurred background. Cool!
But this doesn't work with ordinary windows, either by changing the opacity in the window menu or if the applications have their own implementation of translucency, such as Konsole's translucent background.
also see bug #238141, bespin meanwhile has (basic) support and catches konsole as well (but might actually "break"/override the values set by plasma)
*** This bug has been marked as a duplicate of bug 198175 ***