# treestyletab
**Repository Path**: trusted-list/treestyletab
## Basic Information
- **Project Name**: treestyletab
- **Description**: Tree Style Tab, Show tabs like a tree.
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: trunk
- **Homepage**: http://piro.sakura.ne.jp/xul/treestyletab/
- **GVP Project**: No
## Statistics
- **Stars**: 0
- **Forks**: 0
- **Created**: 2026-03-13
- **Last Updated**: 2026-04-06
## Categories & Tags
**Categories**: Uncategorized
**Tags**: None
## README
# Tree Style Tab (aka TST)
This extension to Firefox provides the ability to work with tabs as "trees".
New tabs opened from the current tab are automatically organized as "children" of the current tab.
Such "branches" are easily folded (collapsed) by clicking on the arrow shown in the "parent" tab, so you no longer need to suffer from too many visible tabs.
If you want, you can restructure the tree via drag and drop.
* Such a tree of tabs will behave like a visual browsing history for you.
For example, if you see a list of search results for a topic, each search result link will open in new child tab.
New tabs opened from these "child" tabs will appear as descendants of their originating tabs.
You'll easily dig and dig deeply, without losing your browsing trail - if you want to go back to the original search result, you just have to switch to the "root" tab.
* Moreover, each tree will reflect a group of tabs on a similar topic.
Please enjoy as you like!
## Release builds
* The signed package of the latest version is available at [Mozilla Add-ons (AMO)](https://addons.mozilla.org/firefox/addon/tree-style-tab/). See also the [`strict_min_version` information in the install manifest](https://github.com/piroor/treestyletab/blob/master/webextensions/manifest.json#L219) to know the minimum supported Firefox version.
* [Old packages are also downloadable on the AMO website](https://addons.mozilla.org/firefox/addon/tree-style-tab/versions/). TST sometimes drops outdated versions of Firefox, but you may find old packages that support the dropped versions of Firefox.
* For even older versions of Firefox, Waterfox, or Palemoon, [Classic Add-ons Archive](https://github.com/JustOff/ca-archive) possibly contains legacy packages of TST.
## Development builds
* Builds for each commit are available at ["Artifacts" of the CI/CD action](https://github.com/piroor/treestyletab/actions?query=workflow%3ACI%2FCD).
Please note that you need to log in to the GitHub to see artifacts.
And you'll need to unzip the downloaded file `treestyletab-we.xpi.zip` manually to extract the XPI package file `treestyletab-we.xpi`, otherwise you'll see an error about invalid manifest.
Development builds are not signed, so you need to load them by an atypical method. (Please click this section to see instructions.)
There are two methods to try them in your environment:
* Go to `about:debugging` and click "Load Temporary Add-on" button, then choose a XPI file. The development build will be loaded and active until you restart Firefox. **Note: don't uninstall the remporarily installed dev build even if you finished a test, because uninstallation clears all configs of TST.** Instead you just restart Firefox, then temporarily installed build are unloaded and the previously installed version will go back.
* If you want to try it as a regular addon instead of a temporary addon, you need to use [Nightly](https://www.mozilla.org/firefox/channel/desktop/) instead of the stable Firefox or Firefox beta. On Nightly, go to `about:config` and set `xpinstall.signatures.required` to `false`. Then you will be able to install such an unsigned XPI file.
Also, you can build a custom development build locally. For example, here are the steps to build an XPI on Ubuntu (native, or WSL on Windows 10):
```bash
$ sudo apt install git nodejs npm jq zip
$ git clone --recursive https://github.com/piroor/treestyletab.git
$ cd treestyletab/webextensions
$ make
```
Steps to build a specific revision (for example bb467286d58b3da90fd1b2e6ee8a8016e3377b97):
```
$ cd treestyletab/webextensions
$ git checkout bb467286d58b3da90fd1b2e6ee8a8016e3377b97
$ git submodule update
$ make
```
Then you will see new `.xpi` files in the current directory. You can install such a development build via `about:debugging`. Click the `Load Temporary Add-on` button and choose `treestyletab/manifest.json` or a built `.xpi` file.
## Extensions that extend TST
TST provides an [API for other extensions](https://github.com/piroor/treestyletab/wiki/API-for-other-addons).
Some extend the behavior of TST's sidebar panel.
See also [the list of known helper addons](https://github.com/piroor/treestyletab/wiki/Helper-addons-extending-functionality-of-TST).
## Similar projects
There are some similar project by someone not me providing similar features:
Vertical tab bar with tree (and more features)
* [Tree Tabs](https://addons.mozilla.org/firefox/addon/tree-tabs/)
* [Sidebery](https://addons.mozilla.org/firefox/addon/sidebery/)
* [ftt](https://addons.mozilla.org/firefox/addon/ftt/)
Vertical tab bar with grouping
* [Container Tabs Sidebar](https://addons.mozilla.org/firefox/addon/container-tabs-sidebar/)
* [Sidebar Tabs](https://addons.mozilla.org/firefox/addon/sidebartabs/)
* [Tab Sidebar](https://addons.mozilla.org/firefox/addon/tab-sidebar-we/)
Vertical tab bar without tree or grouping
* [Tab Center Reborn](https://addons.mozilla.org/firefox/addon/tabcenter-reborn/)
* [Vertical Tabs Reloaded](https://addons.mozilla.org/firefox/addon/vertical-tabs-reloaded/)
* [Vertigo Tabs](https://addons.mozilla.org/firefox/addon/vertigo-tabs/)
* [Sidebar+](https://addons.mozilla.org/firefox/addon/sidebar_plus/)
* [Tabs2List](https://addons.mozilla.org/firefox/addon/tabs-2-list/)
Listing tabs with a search field
Some extensions provide a pop-up list of tabs with a search field that complements TST:
* [Tab Manager v2](https://addons.mozilla.org/firefox/addon/tab-manager-v2)
* [TabSearch](https://addons.mozilla.org/firefox/addon/tab_search/)
* [Tabby - Window & Tab Manager](https://addons.mozilla.org/firefox/addon/tabby-window-tab-manager/)
* [Tab Master 5000](https://addons.mozilla.org/firefox/addon/tab-master-5000/)
* [Power Tabs](https://addons.mozilla.org/firefox/addon/power-tabs/)
* [Tabs2List](https://addons.mozilla.org/firefox/addon/tabs-2-list/): provides not only sidebar panel but a toolbar button with a popup panel also. It has an option to show a search field in the panel by default.
for Google Chrome and Chromium
* [Sidewise Tree Style Tabs](https://chrome.google.com/webstore/detail/sidewise-tree-style-tabs/biiammgklaefagjclmnlialkmaemifgo)
* [Tabs Outliner](https://chrome.google.com/webstore/detail/tabs-outliner/eggkanocgddhmamlbiijnphhppkpkmkl)
* [Treely: Tree Style Tab Manager](https://chrome.google.com/webstore/detail/treely-tree-style-tab-man/hbledhepdppepjnbnohiepcpcnphimdj)
* [Tree Style Tab](https://chrome.google.com/webstore/detail/tree-style-tab/oicakdoenlelpjnkoljnaakdofplkgnd)
for Vivaldi
* [Tree Tabs](https://drive.google.com/drive/folders/0B3jXQpRtOfvSdkN4RW5XN2tOc3c)
Support for Pale Moon, Waterfox, and other Firefox forks
Please use [a forked version of TST for Pale Moon](https://github.com/oinkin/treestyletab) instead.
TST is designed for latest release of Mozilla Firefox (*Please see also the [`strict_min_version` information in the install manifest](https://github.com/piroor/treestyletab/blob/master/webextensions/manifest.json#L203) to know the minimum supported Firefox version), and other applications forked from Firefox are not supported.
"Waterfox Current" looks based on Firefox ESR68 and you can install TST 2.0 and later to it.
However "Waterfox Classic" based on Firefox 56 is never supported.
Support for other browsers based on Chromium (ex. Google Chrome) and WebKit (ex. Safari)
TST can't be ported to other browsers because [it depends on some Firefox specific APIs like `sidebar`](https://github.com/piroor/treestyletab/issues/2801#issuecomment-768584534), so it needs to be re-implemented completely.
Sorry, but I won't re-implement TST as an extension for other browsers by myself because I use Firefox.
(But [there are some alternatives developed by others](#similar-projects).)
Support for Firefox Mobile
Currently I have no plan to add support for mobile devices (Android and iPhone) from some reasons:
* Firefox Mobile doesn't support Sidebar API.
* Mobile devices have limited RAM. Too many numbers of tabs opened by TST may lead OOM killer to kill Firefox Mobile.
How to hide the top tab bar (horizontal tab strip)?
As a workaround, you can [create a `userChrome.css` file.](https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules#for-userchromecss)
But please remind that I - the original author of TST - never recommend such an usage, because TST doesn't cover full features of the native tabs due to restrictions of WebExtensions API so *some tab features become inaccessible*:
* "Autoplay blocked" message and the "Play tab" button image
* "Share" tab context menu command
* "Send Tab to Device" tab context menu command. (TST currently simulates it but you cannot send tabs to mobile devices.)
and I also believe that TST is not enough stable to replace Firefox's tab bar completely.
Thus I usually use TST together with horizontal tab bar for safety.
If I hid the tab bar on my environment in my daily use, I might maintain the userChrome.css hack by myself, but actually I don't do that.
So guidance to hide the tab bar need to be maintained by people who really use.
I think it is a nightmare for regular people who don't know how to research and find out solutions with debugger.
I intentionally don't describe details how to hide the horizontal tab bar, to save people from critical troubles.
I say again, I don't recommend you to hide the horizontal tab bar if you cannot write any suitable userChrome.css hack by yourself.
I have no motivation to investigate how to hide the horizontal tab bar, because I'll never do that and it may lead people to troubles.
How to apply GTK+ theme color on Linux?
Due to restrictions within Firefox, TST can not apply GTK+ theme color to its appearance by default. If you want TST's UI with colors to match other parts of Firefox, you need to configure your environment, Firefox and TST as:
* Set and export an environment variable `GTK_THEME` in your `.profile` or somewhere like: `export GTK_THEME=` (I don't know why but [CSS system colors on Firefox won't respect GTK's theme colors, if this environment variable is missing](https://github.com/piroor/treestyletab/issues/2969).)
* Firefox's about:config
* *`widget.content.allow-gtk-dark-theme`=`true` (not default)*
* `widget.content.gtk-theme-override`=unset (default)
* TST's options (pattern 1, using "Proton" theme)
* "Appearance" => "Theme" => "Proton" (default)
* "Development" => "Color scheme" => "System Color" (default)
* TST's options (pattern 1b, using "Photon" theme)
* "Appearance" => "Theme" => "Photon" (default)
* *"Advanced" => "Extra style rules..." => [paste these lines](https://github.com/piroor/treestyletab/blob/5a8569c22feeaedeecde623a86832db7bc0419a2/webextensions/sidebar/styles/photon/photon.css#L49-L76) (not default)*
* "Development" => "Color scheme" => "System Color" (default)
* TST's options (pattern 2, using less extra style rules)
* *"Appearance" => "Theme" => "High Contrast" (not default)*
* "Advanced" => "Extra style rules..." => no active style rule (default)
* "Development" => "Color scheme" => "System Color" (default)
For more details, please see also [the discussions in the issue #2667](https://github.com/piroor/treestyletab/issues/2667).
How to apply colors customized via Firefox Color?
In short, there is a workaround:
1. Go to TST's options.
2. Choose "Development" => "Color scheme" => "Photon".
3. Add a [CSS declaration applying Firefox's native tab colors](https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules#apply-tab-colors-exactly-same-to-firefoxs-native-2780) to "Advanced" => "Extra style rules for contents provided by Tree Style Tab".
For more detailed background, please see also [my comment in the issue #2780](https://github.com/piroor/treestyletab/issues/2780#issuecomment-746043627).
I cannot find out suitable code snippet satisfying my demand. Is there any reference document?
Sadly there is no stable reference document due to unstableness of TST's DOM structure. The [code snippets](https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules) are just examples for the time they were written, and they may be broken by changes on TST itself, thus they need to be updated by users through [investigation with the debugger](https://github.com/piroor/treestyletab/wiki/How-to-inspect-tree-of-tabs#how-to-inspect-the-sidebar).
Horizontal tab bar
It is not possible for Tree Style Tab to support horizontal tabs.
TST 2.0 and later is implemented as a Firefox sidebar, there is no chance to provide a horizontal version of the extension.
Better support for non-indented tabs
This is beyond the scope of "Tree" Style Tab.
There exist [complementary extensions that can provide vertical tabs without a tree](#similar-projects).
I don't need an automatically organized tree, I want to organize trees myself
You can switch off this behavior:
1. Go to TST's configuration.
2. "Development" section.
3. Expand the section "All Configs". Then all internal configurations are listed.
4. Clear the ☐ `autoAttach` checkbox.
5. Clear the ☐ `syncParentTabAndOpenerTab` checkbox.
With those preferences unset, TST will no longer automatically attach new tabs to a tree.
To select multiple tabs, for drag-and-drop: Shift/Ctrl-click. [Multiple Tab Handler](https://addons.mozilla.org/firefox/addon/multiple-tab-handler/) has additional features.
Add more minor/trivial options
Please see the [list of helper extensions](#extensions-that-extend-tst).
For the appearance of tabs in the sidebar, [custom user styles](https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules) may help.
The variety of configurations for TST will not increase infinitely.
Instead, I hope to reduce the variety.
High customizability is out of scope.
I want to limit options to those that are truly essential.
Too many options would kill this project, because they would cloud the main concept of TST and would attract people who don't share my core vision.
Please see also the [basic project policy](#basic-project-policy)
Controlling where new tabs are opened from links or bookmarks
Available with TST 3.7.0 and later, as an expert option: "Tabs from any other trigger" under the "New Tabs Behavior" section.
[We cannot control the behavior for each detailed case, due to limitations of the WebExtensions API.](https://github.com/piroor/treestyletab/issues/2391#issuecomment-542302281)
High-power management of tree, like sorting child tabs, auto-modification of tree, renaming tabs, and so on
Please see the [list of helper extensions](#extensions-that-extend-tst).
[TST More Tree Commands](https://addons.mozilla.org/firefox/addon/tst-more-tree-commands/)'s [issue tracker](https://github.com/piroor/tst-more-tree-commands/issues) may be a good place to track your request.
Please note that "useful" features won't be implemented to TST itself as a built-in feature.
([There is another FAQ topic, please see it also.](#feature-requests-add-more-minor-trivial-options))
I believe that generally "tree of tabs should be a visualized history of web browsing", because they are built on relations where you came from.
Possibly such a tree is facially chaotic, but it just mirrors your actual footmarks, so you'll easily find out where is the target tab based on a map in your mind. Moreover, those relations themselves may let you recall forgotten idea you thought while you were browsing those tabs.
On the other hand, sorted tabs based on URLs or something will be beautiful - but that's all.
Such sorted tabs won't help me - I'm very forgetful.
In other words, I just need something which memorizes my chaotic mind as-is.
By the way, my another addon [Multiple Tab Handler](https://addons.mozilla.org/firefox/addon/multiple-tab-handler/) will help you if you frequently modify tree by drag and drop.
It provides ability to select multiple tabs by Ctrl-Click or Shift-Click and you can drag selected tabs at once.
Configuration UI to change appearance of tabs in the vertical tab bar, for example, color, height, visibility of the scrollbar, transparency of tabs, and so on
There is a plan to implement an input field to write custom CSS rules, so it will work like as `userChrome.css`.
See the [code snippets](https://github.com/piroor/treestyletab/wiki/Code-snippets-for-custom-style-rules) and [details of inspection for the sidebar contents](https://github.com/piroor/treestyletab/issues/1725#issuecomment-359856516).
Add an option to change the keyboard shortcut from F1
[Firefox itself provides the feature.](https://support.mozilla.org/en-US/kb/manage-extension-shortcuts-firefox)
Better compatibility with session manager extensions, or add high-power session management feature
TST should work well with any other session manager extension together, if it respects [`openerTabId` of `tabs.Tab`](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/tabs/Tab).
[Tab Session Manager (aka TSM)](https://addons.mozilla.org/firefox/addon/tab-session-manager/) is one of examples.
(Moreover, TST also provides an [API to open tabs with structure more safely](https://github.com/piroor/treestyletab/wiki/API-for-other-addons#open-new-tab-bypassing-tsts-tab-control-behavior).
TST and the session manager extension will work together more smoothly, if it opens tabs via the API.)
In other words, TST can't collaborate with any other extension if it does not give `openerTabId` as a hint to construct trees.
On such cases it is required to improve the other collaborator extension itself.
Sadly [it beyonds my power and needs a cooperation by the extension's author](https://github.com/piroor/treestyletab/issues/2914).
As a workaround, you can use TST's bookmarking feature to save trees of tabs.
Select tabs (via Ctrl-click or Shift-click on tabs in the sidebar) and choose "Bookmark Tabs..." from the context menu, then TST creates a bookmark folder and bookmarks under the folder from selected tabs.
After that please right-click on the bookmark folder and choose "Open All as a Tree", then you'll get tabs with restored tree structure.
Better compatibility with session manager extensions, or add high-power session management feature
TST should work well with any other session manager extension together, if it respects [`openerTabId` of `tabs.Tab`](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/tabs/Tab).
[Tab Session Manager (aka TSM)](https://addons.mozilla.org/firefox/addon/tab-session-manager/) is one of examples.
(Moreover, TST also provides an [API to open tabs with structure more safely](https://github.com/piroor/treestyletab/wiki/API-for-other-addons#open-new-tab-bypassing-tsts-tab-control-behavior).
TST and the session manager extension will work together more smoothly, if it opens tabs via the API.)
In other words, TST can't collaborate with any other extension if it does not give `openerTabId` as a hint to construct trees.
On such cases it is required to improve the other collaborator extension itself.
Sadly [it beyonds my power and needs a cooperation by the extension's author](https://github.com/piroor/treestyletab/issues/2914).
As a workaround, you can use TST's bookmarking feature to save trees of tabs.
Select tabs (via Ctrl-click or Shift-click on tabs in the sidebar) and choose "Bookmark Tabs..." from the context menu, then TST creates a bookmark folder and bookmarks under the folder from selected tabs.
After that please right-click on the bookmark folder and choose "Open All as a Tree", then you'll get tabs with restored tree structure.
How to open new "group (folder) tab" intentionally?
A helper addon [TST More Tree Commands](https://addons.mozilla.org/firefox/addon/tst-more-tree-commands/) provides a context menu command to create a new "group" from multiselected tabs.
If you hope to open a new "group (folder) tab" individually, preparing bookmark items to do that may become a solution, because a "group tab" is actually just an internal page with special URL. Such a "group tab" is actually implemented as a local page with internal URL of TST itself. Because of such internal pages have unique host part for each installation due to security reasons, TST provides special URI `ext+treestyletab:group` as a stable alias across installations. For example:
|Title|URL|What will happen|
|-----|---|-------|
|New Group|`ext+treestyletab:group?title=New%20Group`|Creates a new permanent group tab (it won't be closed automatically by TST.)|
|New Temporary Group|`ext+treestyletab:group?title=New%20Temporary%20Group&temporary=true`|Creates a new temporary group tab. It will be closed automatically by TST when there is no child.|
|New Quite Temporary Group|`ext+treestyletab:group?title=New%20Temporary%20Group&temporaryAggressive=true`|Creates a new temporary group tab. It will be closed automatically by TST when there is only one child tab is left.|
There are some more URL options but they are quite internal and unstable. Instead it is recommended to create bookmarks from existing group tabs whici is opened with URL like `moz-extension://xxxxx/resources/group-tab.html?...`, after you configure it with their UI (checkboxes and title input field.) TST automatically detects creation of bookmarks with such internal URLs and updates the saved URL to an alias prefixed with `ext+treestyletab:group?`.