Please add ( i created an account for just this review as its so glaringly obvious an option) the default option when opening the sidebar to be "bookmarks" not "tabs" as mentioned by others. Its a bookmark addon primarily. Let me use it as such. The option to remove unneeded "other bookmarks" and "bookmarks menu" would also help the user experience.

So much more responsive and performant than Tree Style Tab (aka TST) if you have way too many tabs open. This is the one you want.

Perfect

I really don't know how I lived without it before.

Looking for something much, much simpler to use. All I want to do is to quickly group tabs.

Make setting for default panel (bookmars or tabs or ...). I need bookmarks, but it allways open tabs first.

Excellent extension. So much more than just vertical tabs. Panels can be configured to match containers.

Would highly recommend.

it's a great add-on but I'm having a problem with it.
It doesn't work properly with browser.tabs.closeWindowWithLastTab firefox preference.
I have to deactivate it first.

This is the best vertical tab extension. I have disabled horizontal tabs using css so now it looks like it was built in.

If you shift-click select in a search filtered view it selects tabs that aren't shown due to the filter. How did anyone think that was a good idea? User hostile design choice

I was fighting with tabs for so many years. Constantly having a multitude of open tabs, fearing accidentally closing the window.

I was not very productive, having to scroll and look for tabs all the time.

After making the leap to Tree Style Tab, I got comfortable with vertical tabs, and just recently I made the swift to this, more powerful, version.

There are SO many things to configure. Lots of small tweaks. I loved making the sidebar my very own, even implementing a bit of userChrome.css.

This add-on is extremely powerful, as it's so versatile.

I will never look back from this day!