Hi, this is on Arch Linux x86_64, KDE 4.8.1. When I set the desktop theme as air, I usually get a gray panel at the bottom insterad of the normally clear one. The other themes work as expected. I have an Nvidia video card, with Nvidia driver installed and desktop effects enabled. Any ideas?

"Pic or it didn't happen"

Also get a window below the panel and see whether it's actually translucent.
Another impacting element is the blur filter (try to deactivate and/or change settings of the blur plugin in "kcmshell4 kwincompositing")
What graphics chip do you have in particular?

Another potential issue here is an out of date Plasma theme cache, try removing /var/tmp/kdecache-$USER/ outside KDE.

bcooksley wrote:Another potential issue here is an out of date Plasma theme cache, try removing /var/tmp/kdecache-$USER/ outside KDE.

Thanks bcooksley, that seemed to do the trick. I removed the cached theme files and so far so good. I'll keep this tip handy.