Version:            (using KDE 4.3.0)
Compiler:          gcc 4.3.2 
OS:                Linux
Installed from:    Gentoo Packages

When i shade a window (say konsole), most of the window disappears, but a grey rectangle (the same width as the window, roughly double the height of the title bar) remains.  If i move the shaded window, that grey box diminishes to almost nothing.  If I right click on the title bar after that, the large grey box re-appears.

I tried to get a ksnapshot of this with the "window under cursor", but the created image did not show the exaggerated grey box, while on screen it was still present.  However, using the "region" option allowed me to capture the image.