Rated 1 out of 5 stars
With 39.0 version of FF it does not work fine. Buttons from toolbar such as Download, Preferences does not work (only via Menu).This review is for a previous version of the add-on (22.214.171.124-signed.1-signed).
Sorry you're having trouble; why do you think this extension is the cause of the problems you are seeing? It doesn't do anything to the toolbar, so I don't know why it would be impacting that. I'm also using FF 39.0 myself right now and all seems normal.
If you haven't already, please try disabling extensions one at a time to confirm which is causing the problem. If it really is this one, then please enable debug logging as explained on the extension info page and send me the full logs by email.