toolbar misbehaving

[Michael Klinosky <mpk2 enter net>]

Hello.
I installed Fedora 7 on two computer, and one of them has a strange 
toolbar behavior.

Normally, any window (whether visible or 'minimized') is represented by 
an icon in the bottom toolbar. This machine does not do that. There is a 
 graphic in the workplace switcher (at the right). Furthermore, when I 
click the 'minimize' icon at the upper right of a window, it completely 
disappears (and seems to go into the trashcan in the right edge of the 
toolbar).

These two machines have (more or less) identical installations; I 
customized them, so they might be a bit off. Did I skip a vital library 
in my customization?