unlock screen dialog box empty

[Dj YB]

hello,

I have posted this problem in the fedora-kde list but got no replies, perhaps 
someone reading this list know the problem\solution.

when the screen saver is running and I am trying to unlock the screen the 
dialog box is just a gray rectangle (filled) but nothing more, the screensaver 
itself is running great.
so are the plasmoids.
I am using kde 4.4 and NVIDIA driver.
the problem started after the update to 4.4

thanks,
YB.