Session Box not working for Firefox 40.0.3

Same here! Is there a fix or workaround?

I posted about it also, three weeks ago here: https://fvdmedia.userecho.com/topic/887910-sessionbox-for-firefox-no-longer-working/
No reply yet. It would be nice if they can at least acknowledge that they are aware of the problem.

BTW,

Note to Administrators:

With all due respect, this message board is very disorganized. Why have a forum called "Firefox Extensions" and then also have separate topics for individual Firefox extensions? You end up with different people posting about the same problem in totally different sub-forums. Why not streamline everything so people know exactly where to post? It will make it easier for you to track and respond to bugs and comments, and you can eliminate duplicate posts.