Comment 42 for bug 600178

Are you sure that it does not happen with mutter? As far as I can see it happens in any type of session – unity, classic, classic with no effects, unity 2D, even if I explicitly call mutter --replace. It is true that it is nvidia-specific though.

It might be interesting to find out whether this issue is present in other distros – Fedora 15 has just been released, perhaps it uses xserver 1.10 and the current nvidia driver.