First, thank you very much for your work on this addon.
With this new Waterfox version, the addon doesn't load, i don't know since which version it doesn't work because i just installed CS for the first time.
Thank you for the fork! Two of my indispensable extensions are All-in-One Sidebar and Tab Tree (https://github.com/traxium/tabtree). Unfortunately, I have random display issues of Classic Sidebar when enabling Tab Tree. Also, the buttons stops responding. I would be very happy if you could get CS to work with Tab Tree!!