Anonymous user 097179 ty for great explanation!!! Now all works right for this great extension!

Been using this addon for years now, and tried a few alternatives, but nothing ever came close.
The developer Piroor is also very active on his GitHub.

Not Piro's fault for the top tabs, that is Firefox's new API limitation and Piro has gone to great lengths to get it this far. Just a simple couple of steps to get rid of the top tool bar if you read the bubble information in the new update or just look for the links in these reviews.

Still an indispensable addon for Firefox. I like the new version and thrilled it made it over to the new version 57. I wouldn't use Firefox without it to be quite honest.

Thank you Piro, been using your addons for years. My workflow would not be the same without them.

For those that can't be bothered to educate themselves, here's a copy/paste from someone that took the time to write out step by step instructions. Takes less than 2 minutes to do.

If you're like me and primarily used this add-on to remove the tabs from the top, follow these instructions provided by user Soulyaris:

"Inside your profile folder(it usual c:\Users\*user*\AppData\Roaming\Mozilla\Firefox\Profiles\*something*-default (check date of modified),
Create a new folder named chrome.
Inside the chrome folder, create two new files, userChrome.css and userContent.css.
At the top of userChrome.css, add (copy/paste) the following:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
/* Hides tab bar*/
#TabsToolbar { visibility: collapse; }

Save it and restart firefox. Enjoy."

That's it, enjoy tree-style without the top tabs.

What can I say: were it not for this addon, I would not be using Firefox. Piro has undertaken a thankless, herculean task to rewrite from scratch a very mature extension using a new, immature API, wrestling with its many limitations, working with Mozilla to extend the API to bring this add-on, and many others, up to more usable levels.

There are many rough edges with this new WebExtensions version of TST, but it would be impossible to penalize Piro for those, as I see just how much effort he his putting into bringing the best possible experience to his users.

WebExtensions or not, TST is utterly indispensable. And it will only get better from here.

(Piro: I understand how demoralizing it must be to get these 1 star reviews from users who don't know any better. Hope you're sufficiently able to ignore them.)

-

ffffffrf

It's a must have! Thanks.

It's just the Firefox 57 upgrade that is a bit hard but it is not the developer's fault! I was just surprised not to see my vertical tabs on the left (even after some FF restarts) until I read that there is a button to display it! Maybe there is a bug or the developer simply forgot to make this visible by default or maybe FF57 does not allow this.

For the upgrade, I had to follow the migration tutorial here: https://github.com/piroor/treestyletab/wiki/How-to-convert-session-information-from-old-TST-0.19.x-to-new-TST-2.x
And then I used the following CSS rule to hide the "standard tab bar on the top": https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules#hide-horizontal-tabs-at-the-top-of-the-window-1349
First I had to created a folder chrome inside my user profile directory, then a new file userChrome.css where I placed the following code:
#TabsToolbar {
visibility: collapse !important;
}
This hides the "standard tab bar on the top" as expected.
Now I finally have TST quite as before, and at least as usefull as before!

Thanks again @Piro and other developers to keep maintaining this add-on!

works great with WebExtensions!

It works great with firefox 57. Almost like in 56 but need to configure it a little bit. Use github instructions to get TreeStyleTab which it was at firefox 56.

На firefox 57 работает практически также как и на 56 с небольшими допилами. Используйте инструкцию на гитхаб чтобы сделать всё как ранеьш.

JHP - Many thanks for referencing the code to remove the horizontal tabs. Can you tell me the name of the 'user profile directory' folder, as I can't find it in Windows Explorer.

There is just nothing else like it. Nesting tabs allows you to have many many tabs open while staying organized. This is excellent for research as you can nest result pages of a google search under the google page - which also provides a conveniently named header. The drag-and-drop interface is intuitive and responsive. It is also reasonably customizable. I would be seriously sad if this extension were to go away.

I love tree style tab. Tree Style Tab has brought order out of chaos for me. The whole internet experience is much more organized and enjoyable with it.

In the latest version for Firefox Quantum there is an icon to show/hide the side panel. Before I sometimes had problems with the tree panel not rendering completely and I couldn't see the show/hide bar to hide it, that problem is all gone now.

One thing I don't like about the latest version is that the standard tabs are now at the top and not hidden when the side panel is visible. Sometimes when trying to move the window I accidentally click on one of those tabs.

Another issue is that the side panel has a header at the top. I assume that header will be useful for someone who has more than one side panel installed, but for me right now it is not useful.

MUST HAVE & BEST addon even with 360 tabs grouped on the left side. Good performance even with 5GB RAM used for DNA & engineering on 64 bit FF ESR. I will stay on ESR 52 (32 and 64 bit FF) until this addon is properly and fully supported by FF and addon creator. If I have to I will stay with ESR 52 even when it is no longer supported in 2018. And I don't care if TST has some bugs; they're mostly minor and mostly affect the special case of 1 tab or 1 group of tabs. Work-around is to just have 2 tabs opened or more and it's perfect. I would pay $$$ to Piro for his great work !! Prior to using ESR I was fed-up with many addons and icons breaking with every FF update. I dreaded the updates but there's the security issues. I was spending way too much time repairing FF (non-ESR). Intel i7 and 16 GB RAM underused. They should have kept the older addons in a sandboxed/container within a 1 single thread. And add the newer web-extensions in their new multi-thread machine to avoid killing decades of software by hardworking dedicated addon developers. So much addon software destroyed in 1 swoop :( And I have over 50 addons. Even with the very hungry NoScript and other necessary privacy and security addons.

E' così comodo in verticale tutti i tab

If you're like me and primarily used this add-on to remove the tabs from the top, follow these instructions provided by user Soulyaris:

"Inside your profile folder(it usual c:\Users\*user*\AppData\Roaming\Mozilla\Firefox\Profiles\*something*-default (check date of modified), create a new folder named chrome. Inside the chrome folder, create two new files, userChrome.css and userContent.css. At the top of userChrome.css, add the following code:
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
/* Hides tab bar*/
#TabsToolbar { visibility: collapse; }
Save it and restart firefox. Enjoy."

Really great add-on. I'm sad to see one of its core features get changed. I hope it gets fixed.