Thanks for this addon!
I really like the native tab bar, but I also like how Tree Style Tab groups related tabs together. So I created an addon based on this addon that colors the native firefox tab bar based on the group the tabs are in.
https://addons.mozilla.org/firefox/addon/tab-groupcolor/ (please don't break the dependency :))

First: If you think the add-on doesn't work, press F1 or click the "Tree Style Tab" button that appears. The options page tells you this, but we all know people are too impatient to read the manual and expect everything to be done for them instantly.

Due to current limitations with WebExtensions (in Firefox 57.0.2), this add-on can't remove tabs from the top of the screen, so the user has to do this themselves by modifying their userChrome.css file. There is a post on the Firefox subreddit detailing how to do this, but I would like to see this guide included or referenced in the options page until such functionality can be added to the WebExtensions API: https://www.reddit.com/r/firefox/comments/736cji/how_to_hide_native_tabs_in_firefox_57_tree_style/

Caveats aside, Tree Style Tab is still an exceptional organizational tool for anyone who has a habit of opening new tabs for everything. With the tree organization, you always know which tab opened from or is related to which other tab, and the options for how you want the tabs to behave are extensive. The only faults I can find have to do with limitations of the new add-on engine, so I can't think of any reason to deduct stars. Great add-on, essential to how I navigate the web.

Nice integration in FF57 !

Can you add a configurable keyboard shortcut so we can fast switch between bookmarks (CTRL-B) and Tree Style Tab (CTRL-something) ?

Is there any way to save a Tree Style Tab session and get the tree as identical when loading it ? When I use Tab Session Manager the tree is lost :(

Thanks !

Amazingly useful addon. Makes tab management so much easier that I couldn't use a browser without it.

Tree Style Tab was a major reason I kept coming back to Firefox after trying to switch to Chrome. Now that Quantum has sped up Firefox, I'm so glad there's a WebExtensions version of TST and it works pretty much as well at the old one, but less laggy!

just works

I'm so happy to see this has migrated to quantum. Huge fan and glad to see it will continue!!

This addon is literally the only reason I use firefox.
Works perfectly. Thank you for all the support and upgrades.

Just needs some magic after upgrade to FF 57 to hide the native tabs on top of the screen (which is not the developer's fault) - see below and in other reviews as well, you can find additional information on how to do this
Also see the wiki page for this addon - there are examples for styling the tabs:
https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules

To hide FireFox tab bar and Side Panel title:
1) Locate your firefox profile folder (you can find it in the troubleshooting section in the Settings)
2) Locate "chrome" folder there - create it if it isn't there
3) If there are no files userChrome.css and userContent.css in "chrome" folder - create them
4) At the top of userChrome.css file add:

/* add this line if it is not there */
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

/* to hide the native tabs */
#TabsToolbar { visibility: collapse; }

/* to hide the sidebar header */
#sidebar-header { visibility: collapse; }

==================================================================================================

Чтобы скрыть вкладки вверху браузера, см инструкцию ниже, а также прочие отзывы. Также см вики для этого аддона - там всякие примеры, как стилизовать вкладки: https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules
1) Находим папку профиля firefox - Настройки - Справка - Информация для решения проблем - Папка профиля - Открыть папку
2) Если в ней нет папки chrome - создаем
3) Создаем файлы userChrome.css и userContent.css в папке chrome, если их там нет
4) В начале файла userChrome.css добавляем:

/* добавить эту строку, если ее там нет */
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

/* чтобы спрятать вкладки сверху браузера */
#TabsToolbar { visibility: collapse; }

/* чтобы спрятать заголовок у сайдбара */
#sidebar-header { visibility: collapse; }

This the one, the only 10-star add-on.
5 stars for the value of its mission
5 stars for execution
Firefox has some work to catch up to where it was before, but it can still handle this add-on quite well. Visual, collapsible tab tree just makes the browsing experience so much more sensible.
I'm looking forward to seeing the weird old tab bar disappear again, but that's a problem with WE not with this add-on.
I can hardly remember a time I was this happy with a browser feature since the invention of the DOM inspector.

most valuable firefox extension, and in fact the only reason to use firefox. thank you!!!