mouse response sluggish in fullscreen firefox

Binary package hint: compiz

REPRODUCE: Open fullscreen (not maximized!) firefox, go to a webpage which fills a couple of screens vertically so you get a vertical scrollbar. go to a text only page so that you know that the page itself is not a resource hog. NOW: 1) use the left mouse button to click and drag the vertical toolbar. on my system there is a ~1sec lag before the window reacts to the mouse click at all. 2) click and hold on some text, wiggle your mouse to select text. notice the ~1 second lag here too. very inconvenient. switching the window out of fullscreen mode makes it react like normal, quite instantly.

This is gutsy, updated/upgraded via apt-get yesterday, running on a lenovo thinkpad x60 w/intel 945 graphics. OpenGL programs work nicely on this machine, with compiz they are somewhat slower. I run the normal X server, not Xgl, since when I enable Xgl everything except panning between workspaces gets very slow (wobbling, for instance).

I have enabled "extra" desktop effects - wobbling, panning workspace switching (not the cube). I run many workspaces and switch between them with ctrl-f1, ctrl-f2 etc.

I usually dedicate some workspaces to running applications in full-screen (not maximized, but full-screen) mode - an xterm for irc on one workspace, a fullscreen firefox on another, etc. Normally I have a desktop shortcut (shift-ctrl-enter) to toggle fullscreen, so i use it a lot.