Drop shadows in Debian Lenny KDE4 occur under sort of tool tip boxes and stuff like that, but they do not occur for actual windows themselves. A window does not throw a shadow on the desktop background or on a window underneath it.

So the KDE configuration is working - I may adjust the shadows under the things that appear when a mouse hovers over some button, for example - but there are no shadows for actual windows: which is the main idea. Using a backport, if that's important. Any suggestions hugely helpful.