Liking this so far, lots of nice features, but haven't tried them all yet. The groups feature is a welcome addition. I could say this is an addon that could replace a bunch of other ones I have (session saver, tab groups) if the tab group import and expert, and the tab session import and export worked for me, at least it doesn't right now on my Mac, High Sierra. If it works on Windows that'll do me as that's my main power user machine anyway.

Issue I am having on the Mac is that the export saves it as a csv, and importing looks for *.tt_group or *tt_session - renaming the extension from csv to the correct one it's looking for, or just trying to load in the csv - both methods result in nothing happening.

Also the search feature would be better if it just showed the matching tabs rather than highlighting them. But personally not a feature I can see myself using much as I'd just search using the address bar.

Good effort though, switched from Tree Style Tabs as half the time the tab side pane would just load endlessly and never complete.

EDIT- the import/export works well on Windows, but it crashes my Firefox A LOT :( weird, as I don't have this problem on my Mac. It will hog maybe around 50-60% of my CPU :/ disabled for now, but I really want to re-enable it later down the line, I really want this addon to do well.