With MOZ_DISABLE_PANGO=1 the wrapping bug doesn't occur at all -- i.e. the long text on the page is never wrapped.
Seems it's Pango-related. Seems this was already reported as bug #46034 -- firefox crashes/freezes X with nvidia on some pages https://launchpad.net/bugs/62492 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
