I think so, haven't tried to be honest, but this article http://winaero.com/blog/how-to-disable-australis-in-firefox-and-get-back-the-classic-interface/ http://

I think so, haven't tried to be honest, but this article http://winaero.com/blog/how-to-disable-australis-in-firefox-and-get-back-the-classic-interface/ http://winaero.com/blog/how-to-disable-australis-in-firefox-... Also this only affects the nightly and add-on developers should be testing nightly anyway so they should prepare to update their add-ons in the future to adopt to the new UI.