Gadgets stopped working with Firefox 19

In Firefox 19 (Ubuntu 12.10) gadgets stopped working. It seems some work partially/sometimes (yes/no/mini, map) but most of those tried are completely broken (yes/no/maybe, yes/no/maybe+...). With FF 18 they were working. With websockets disabled in FF 19 gadgets still don't work. From Chrome/Chromium they work perfectly. Firebug aborts some requests to opensocial.googleusercontent.com (example in a comment).