Seems to happen in all cases were Firefox wants to Display a error message in based on a xml message. In my case it mentioned it, when the page isn't reachable or some kind of 40x error happens or a certificate warning should be displayed.
-- Firefox can't display error pages anymore https://bugs.launchpad.net/bugs/218563 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs