Rated 4 out of 5 stars

Great addon, but only older version 1.2.8.4 working for me too! (FF 24 and even FF31)

This review is for a previous version of the add-on (1.2.9.1-signed.1-signed). 

With AC 2 1.2.9 installed go to add-on options, uncheck all options and restart Firefox. Now set options for AC 2.