Previously I discovered that KDE SC 4.6 and X.org server 1.10 in Debian Wheezy are not a happy couple for various reasons. One of them is the garbage appearing behind new windows even on non-compositing window managers regardless of the DDX in use.
The issue appears to be tracked, in fact, as bug #31017 in freedesktop.org’s Bugzilla. Unfortunately, it’s classified as being of medium/normal importance, it’s been sitting there for some time while other entries get marked as duplicates and I hear rumors that X.org server 1.11.0 is coming out soon.
I guess I can only hope later versions of the 1.11 branch integrate a fix of some sort. I’m starting to doubt I’ll be able to stick to Debian Stable for much long, especially if I buy a new laptop this year — right now I’m compiling GCC 4.6.1, that’s not a good sign.