Broken. This is my favorite add-on but it has stopped working in a catastrophic manner and I just lost all of my tabs. The "bring all tabs into Onetab" function closes all the tabs and windows *but doesn't add them* to the one tab extension. It just threw away all of my tabs. This worked before firefox 57 and yes I am using the updated version. I even uninstalled, restarted, installed the latest version, purposely opened multiple windows with multiple tabs and tried again just to test it... only for it to fail again in the same way. Now I have to go through the history and manually find the 50+ tabs it trashed earlier and switch back to Chrome. They don't even show up under "recently closed". This add-on is essential to my workflow so Chrome is the only option now. tldr: Works perfectly for 1 window, fails epically at multi-window. Was a 5 star, now a 1.