Rated 4 out of 5 stars

If it is broken for you on FF35 it is probably because you have dom.indexedDB.enabled set to false in about:config -- I set it to true and it 'fixed' this extension and a whole bunch of others. It sounds like FF36 will fix the underlying brokeness. http://forums.mozillazine.org/viewtopic.php?f=23&t=2876819