1. fill up your workspaces [of desktop wall] with windows (make sure they're easy to tell apart)
2. run "xrandr -s 800x600"
3. observe that some of the windows are not on the workspace they were before you ran xrandr
I think it'd be better if windows stayed on the workspace they were on when the screen resolution got changed.
(compiz --version says I'm running 0.7.9; I got that one outta' git, so I'm putting "git" down in the version field, even though I got it a while ago)