2-5-20 Review update:
I agree with Korkenwine review, the lack of Tabs Search options is a major missing option. Like many, when doing extensive online researching or shopping, I can easily have over 1K - 2K Tabs open, can get very hard to navigate in TST, do not always have time to go thru & clear out unwanted research tabs daily, that is why TST would be best to stay on top, to help quickly save multi list of ever growing tabs for later.
Again, TST is problaly the best (All in one) extension have found in last few years,but after so much troubleshooting, just cannot get TST to work consistently.
I am also using a fairly new Windows 10 64Bit Acer laptop, (not a 32Bit). I have ( 16GB RAM 1TB STORAGE), so I doubt if my PC hardware is the issue, as even most of the outdated Tabs extensions tested work, but have disabled them, due to lack of addtl options or updates. So my search, (would gladly Pay for even) for the closest TST addon & Full Tabs Mgr continues, until it gets worked out. Cheers!
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Great concept, after trying hundreds of addons, TST has to be one of the top extensions , with most useful features if have many Tabs, & need in user friendly vertical drop down view, for quick navigation & saving, So we do not have to keep installing & removing several outdated junk extensions , that only do a few basic Tab management options in Windows 10 PCs.
**Really wish Firefox & other Top browsers, would create a built-in browser extension like Tree style tabs , with most useful features if have many Tabs need in user friendly vertical drop down view, for quick navigation & desired selection of Multi Tabs saving & bookmarking etc.

Even though Tree style Tabs is a great concept, but like others have said, it just has far too many
Bugs & issues , so cannot even use it hardly at this time.
Like many, I also Used to use the older Tree style Tabs version until it, like most addons became outdated, & full of issues.
Was very excited when this new version was released recently, with many more options, but sadly, have still not been able to get it to work correctly last few most current Firefox versions.
TST loads all of my few hundred Tabs in vertical TST Sidebar, but that’s it, cannot search thru, or scroll
Thru more only 12 tabs out of a few hundred, TST doe nothing, tree style keeps freezing up.
After spending days & hours scouring thru all the Tree style Tabs FAQs, & support forums pages,have always had bug reports enabled, also keep restarting cache, unchecking & rechecking all options, many times, to no avail.
Like many, just do not have nay more time or energy to diagnose why TST addon not working still.
***Would be great (if TST Developers put in a Built-in Errors & Bugs troubleshooter & Fix option) so we do not have To keep trying to figure all TST's issues & bugs with each Browser version update.

Again great concept, could be the one of the Best extensions ever, if developers could
Work out all the ongoing Sidebar Tabs issues & bugs, most other Tab Managers do not have all these issues, So can finally use TST, without all the ongoing headaches.
My online Reviews of Tree style Tabs Rated ( 2.6 out of 5 Stars).

A usefull addon, but when I open a tab open after two tabs. I changed the options, no fixed

Great extension while it is running, but each time the firefox is restarted it's a pain because all tab hierarchy is broken.

Need a feature to auto-backup and manually save/restore tree.

I thought that the giant grey bar it makes is intrusive, also I dont like it zooming out the page at at. A transparency setting would be great. Ways to make it smaller and less intrusive to the website would be nice as well.

This extension bugs out a lot, forgetting the positions or tabs between plugin crashes and even between F1 sidebar toggle presses. I LOVE it when it works, but I HATE it when it doesn't, as it takes at least 5 minutes to fix the mess it creates when it breaks. (All the tabs are randomly ordered, parents forgotten, some tabs are even missing from the tree altogether and exist as "ghost" tabs between ones actually in the tree!)

Brilliant idea, poor solution. Unstable a buggy in all versions.

This is great.. when it works. When it breaks Tab indents, it's impossible to fix.

Most important basic function is missing!
-indenting/outdenting tabs can only be done with drag/drop, and very inconsistant.
-when parent tab becomes independent you need to drag and drop each and every one below it back.
-NEED simple keyboard shorcut or option menu or UI shortcut (left/right arrow) to indent/outdent.





Stuff to fix
--indent and outdent current tab: need keyboard shortcut or context menu (drag and dropping is a bit too hit/miss)
-new tabs/"insert to the top of the tree, as the first child" doesn't work with Ctrl+T
-keyboard shortcuts are not modifiable
-some recovery issues with Tab Session Manager.
-but a bit unstable and Laggy after about 80+ tabs
nice to have!
-backup / restore settings?

I've been using TST for about 6 weeks, and it's worked fairly well, but it's got at least two annoying problems.

First, when I open a link on a page and specify that it's to be put into a new tab, TST will occasionally create the new tab in some random location farther down the tab stack (but not as a child of the active tab). Trying to move that new tab back under the active tab is fruitless--it always jumps back to the random location.

Second, whenever I restart FF, TST doesn't retain the tree structure that existed before the restart. The first group is always as it should be, but beginning with the second group, all subsequent groups become child branches of the second group or some other subsequent group. It's a real mess, and it takes me a good 3-4 minutes to manually put things back the way they should be.

Hopefully, all this will go away in time. I should note that I'm running Tab Session Manager, though I don't think the problems started when I installed that (about 4 weeks ago).

Inserting new tabs do not respect preferences set in this addon for Firefox Quantum. It appears the plugin does not actually respect any of its own settings. If I press CMD + T on Mac, it always goes to the bottom and makes a new tab tree. Never does it make a child tab.

Not working on FF 57 57.0.4 (64-bit) Manjaro.

It does not seem to work because it only shows open tabs--it does not show how I got to the latest site. The sidebar shows all of the current tabs but it doesn't show any children if I click on a link on the page represented by the tab. Can't figure out how to get it to work.

It's a very big UI flaw that I can't open my bookmarks or history up along side the tree tabs (as they are both stuck in a single sidebar pane). Please complain to Mozilla about this.

とても便利に使えていますが、大量にタブを抱えていると落ちて復旧するときにツリー構造が破壊されることがある感じがします。
上のほうにあったタブ群が下に来たり、子タブがぶら下がってるタブがただのフォルダのようになって内容が復帰しなかったり、その子タブの一番下のタブを閉じるとなんか反応があったり。
Tab Session Managerとの併用なのでどちらの問題なのかはよくわかりません。

Так изуродовать прекрасное дополнение ... Это надо было приложить массу усилий.

Firefox 57 has completely ruined this add-on. Highly unfortunate as I read online to see if there would be any issues before updating and it didn't look like it would be a problem.