Comment 0 for bug 1138473

See https://bugzilla.mozilla.org/show_bug.cgi?id=846863.

This didn't really appear on the radar because of a problem with debug symbols for system libraries, but now that's been fixed this week.

libunity-webapps is pulling gtk3 in to the address space of Firefox (which is gtk2). They absolutely do not work along side each other in the same address space (gtk2 refuses to even initialize if it detects gtk3 symbols in the same process, but this check is bypassed because it's initialized before libunity-webapps is loaded), and having them both in the same process is not supported in any way whatsoever.

I've no idea why this has only started being a problem now (perhaps it's the cause of a lot of random crash bugs / hangs that we get reports of). I can only think that Firefox used to do something on startup that indirectly caused the registration of the GdkKeymap type (in gtk2) before the webapps addon loaded, and now that doesn't happen until afterwards - by which point it has been registered in gtk3 code, which results in type registration failing later on.... and then it's a guaranteed crash.

This is the sort of problem that's likely to explode due to a slight change in wind direction, which has now happened. For people experiencing this, it's a startup crash (meaning that Firefox is completely unusable for an unknown number of our users).