I've been primarily using iceweasel (based on ff10) with the system cairo as that is many times faster for gfx. But I've also been using the bloated ff from ubuntu and fedora on different systems (and they use the ancient cairo embedded into firefox). There are a lot of differences in cairo between those versions, so it would not surprise me if it was a bug specific to an older cairo. But I've hoped to have seen it by now as well. :|
I've been primarily using iceweasel (based on ff10) with the system cairo as that is many times faster for gfx. But I've also been using the bloated ff from ubuntu and fedora on different systems (and they use the ancient cairo embedded into firefox). There are a lot of differences in cairo between those versions, so it would not surprise me if it was a bug specific to an older cairo. But I've hoped to have seen it by now as well. :|