ALT-TAB no longer working?

[Scott I. Remick]

> It's in the Keyboard Shortcuts capplet as "Move between windows 
> with popup".

Hmm I think there's something borked with my Keyboard Shortcuts. I can't
find "Move between windows with popup" in it. I have 3 top-level
categories: Desktop, Sound, and Window Management. The first 2 have
twisty-triangles next to them for expanding the category. One
would think Window Management should too, but it does not and so it's
effectively empty. Logically I'd think that "Move between windows with
popup" would be under there, but I can't get to it.

Given this, any suggestions on repair? Thanks