This tab seemed cool & useful at first, but then it's limitations started to rear their ugly head. I haven't quite been able to determine if this addon is made for power users or not. I dumped upwards of 700 tabs in here. What's readily apparent is sorting was not thought about in this extension. It's a bit cumbersome & requires too many steps. In addition, at this level, things seem to break: I'll send 10 tabs at a time to a group & it just does nothing, refreshing the page. It...sort of works? I'll have to see if there are any conflicting add-ons (e.g. uMatrix or uBlock) that cause issues. Otherwise, I've set myself back the equivalent of months by using this.

Edit: *sigh* I've adjusted my review, as I realized there's a toggle in the options to 'silently' ignore duplicates. Perhaps this shouldn't be silent for those of us who are coming from other tools like TabGroups & TabGroups+. I'm still leaving my review in-tact, as I think the developer will appreciate some of the suggestions. Or not. :-)

Also, I will say one thing. As a result of installing this add-on, you realize how fast it is to just 'WOOSH', send many webpages into oblivion. Kinda neat.