just an annoying sidebar with no function
Firefox already has multiselect tabs built in, just Ctrl or Shift click on tabbar and right click to select your action

Seemed like it would be useful to move a group of tabs to a new window, then use Bookmark all tabs to save them to a folder. Somehow I ended up with about 3-4 new windows, some of which just had a blank tab. One of my other tabs became unpinned and all my tabs got rearranged. Firefox asked if I was sure I wanted to close 126 tabs (certainly NOT - no idea what triggered that). Got my tabs back thanks to a sessionstore backup. Hope this was a major anomaly, but I'm uninstalling. If you choose to use this, be very careful. At the very least the add-on needs some documentation on how to use it, and that needs to be in an easy to find location, preferably right on AMO.

Do nothing useful! Awful