Comment 107 for bug 940603

So we see this consistently, and it seems to happen (sometimes) when Chrome pops up a new window (I see it when gchat creates a mole, or when a link opens in a new tab, though not always). The size of the white box is the size of whatever window was being created.

The white box is not a window; X events go to whatever is "underneath" as if it weren't there, and xwininfo doesn't see it.

Restarting compiz reliably makes it go away (but has other annoying side effects, like making the upper-right icons no longer responsive to input).

As you can imagine, we have a lot of Chrome users, and this is a very significant usability problem for us.