For those concerned about one of the most recent TST updates (I believe it's 2.2.8) that requires your permission to "Access your data for all websites", note that Piro addresses this concern in issue #1536 on TST's github project, specifically in the following comment: https://github.com/piroor/treestyletab/issues/1536#issuecomment-344792173.

I was concerned about this permission request at first, especially since I have enjoyed TST for so long and didn't want to stop using due to permission overreach. However I think I can accept the risk based on Piro's explanation of why Firefox issues the warning.

Thanks for the great add-on, Piro! I really appreciate your hard work :)

Can't imagine my browsing experience without this extension. Has been using it for many years. Must have, best of class!

I already use it for long time. great for my 800-900 tabs.
firefox update to 57, with no warnings...
firefox say TST is the same and took my session manager.
now all my trees become flat !!
I tried to use the migration cmd tool on the last session file, but it give access denied and also the exe can not be erase from my folder :-(
I also does not understand all the config in the advance section of this add-on.
just to mantion, it keeps new trees as created.
I could not find firefox 56 download, in order to downgrade.
how can I get all my tree structure back ?
TST 2.2.8
thanks

Awesome.

One of the most useful extension and the number one reason why I use Firefox.

Really nice Add-On, especially for the fact that I can edit the CSS inside the settings.
Just one thing: Would it be possible to add an option to set the animation speed or transition time?

Using it for a long time now... I love it... Firefox should have vertical tabs by default, its way more intuitive to scroll up/down than to move the tablist left/right, and its more productive since pages are vertical usually and vertical space is more precious nowadays

The tree feature is the best grouping/tracking of set of pages

The only thing this addon lack is the coloring of the tabs, would love to see that feature in a future release

To change the size of the tabs do:
/* Change tab height */
.tab {
height: 24px;
}

Following the message of XenGeek
I used this code to remove Tabs keeping the title bar.

/* Remove horizontal tabs */
#tabbrowser-tabs {
visibility: hidden;
margin-top: 40px;
margin-bottom: -50px;
}

/* Remove sidebar header */
#sidebar-header {
visibility: collapse;
}

Anyway this add-on is very good, I don't understand why this tree tab menu is not a standard in Firefox. Saved me a lot of time and energy !

Thanks a lot !

Extension is very handy. But last update asks for accessing all my web data. Why??? I'm not installing it for now cause there is no justification anywhere why this permission has been requested.

To add on to Anonymous user fc7bf5's comment. If you want to get rid of the Horizontal Tabs and the Title Bar for the sidebar simply add the following in your Firefox Profile. This is not the Local AppData one, but the Roaming one which is normally found at: %UserProfile%\Appdata\Roaming\Mozilla\Firefox\Profiles

You will have a profile folder here, maybe more if you utilize multiple profiles in Firefox. Once you pin-point yours you simply need to add a new folder called "Chrome" in your profile folder and create a new text file "userChrome.css" make sure it is a css file and not a txt. you may have to google how to change file extensions by revealing them in Windows. The contents of that file should contain one or both of the following segments depending on what you want.

/* Contributed by Anonymous user 099626's */
/* Remove horizontal tabs */
#tabbrowser-tabs {
visibility: collapse;
}

/* Remove sidebar header */
#sidebar-header {
visibility: collapse;
}

Once this is done you will have to restart FireFox. Depending on your theme in FireFox you may notice you can't see the windows control buttons in the upper right. To fix this simply go to the "Customize..." menu and check the "Title Bar" option then click done.

ps. I've noticed some FireFox menu's don't take the removal of the Horizontal Tabs into account due to it not being a build in option. With this in mind option screens like "Customize..." may take over your full screen including the TreeStyle Tabs. If this happens simply look for another way to close the screen, which should be provided.

pps. TreeStyle Tabs is a fantastic app that I've used for years, I've slowly started moving to Chrome because of the noticeable speed difference and the large amount of multitasking I have to do daily. I am excited to see if FireFox Quantum can live up to the speed it boasts. That being said...

Happy Tab Hoarding! :D

Thanks to Anonymous user fc7bf5 for fixing the problem to remove the tab bar at the top!

With this fix 5 stars. Strange that the creator of this usefull extension didn't solve this problem.

For anyone having trouble with the horizontal tabs not hiding, Anonymous user 099626's advice worked for me. Create a folder chrome/ in your firefox profile and then in that directory a userChrome.css file containing the following rules

/* Remove horizontal tabs */
#tabbrowser-tabs {
visibility: collapse;
}

If you want to get rid of the sidebar header, add this to the file:

/* Remove sidebar header */
#sidebar-header {
visibility: collapse;
}

You will have to restart Firefox to enact the changes.

Best extension ever that keep me using Firefox

Must have дополнение для ФФ. Пользуюсь уже много лет.

ツリー型タブのアドオンを1年前ほどからずっと入れてましたがFirefoxのアプデにより
ツリーの固定化と最大縮小サイズが狭くなってしまいもっと狭く設定できるようにしてほしいです。
このアドオンを使わないと生きていけない体になってしまい、とても良いアドオンだと思います

Practically essential if you open many tabs. Hierarchical indentation is what makes this superior to all other solutions.

The transition to Web Extensions is excellent considering the situation. There is a current bug on Firefox's end that keeps the horizontal tabs around. You can address this by creating a file in your Firefox profile, \chrome\userChrome.css and add the following rules:

/* Remove horizontal tabs */
#tabbrowser-tabs {
visibility: collapse;
}

If you want to get rid of the sidebar header, add this to the file:

/* Remove sidebar header */
#sidebar-header {
visibility: collapse;
}

You will have to restart Firefox to enact the changes.