Desktop thumbnails do not show app images

openSuse 11.2, linux 2.6.31.12-0.1-desktop x86_64
gnome desktop

I run Virtualbox (v3.1.4) to continue using os/2 for a couple of non-portable applications. VB has a habit of crashing linux on occasion: a complete system freeze. (Reported to VBox developers, ignored so far.)

After one of these freezes and restarts, the graphics (ATI Radeon hd3200) was no longer accelerated. So I installed ATI’s custom video driver. That restored the acceleration.

Here is the reason for the post: On the gnome panel are a little set of icons (thumbnails?) for the different desktops available (I stayed with 4). Previously, the window with the focus in each desktop showed its apps’ icons in the thumbnail regardless of which desktop was active.

Now, only the desktop that is active shows the icons of the apps within it, instead of all of the desktops. As I switch from desktop to desktop, the icons appear and disappear always showing 3 empty desktops.

Any idea how to restore the original behavior?