• Edge-like vertical tab design
  • Tree style tab layout support (works with Sideberry & TST (legacy) version)
  • Dynamic Indentation
  • Automatic theme configuration for light and dark themes
  • Custom theme configuration using Sideberry
  • Support for tab groups
  • Support for Tab Containers with visual identification
  • Pinned tabs (right click to close)
  • Built in CSS Extension Management


Click here to view FirefoxSidebar on GitHub

This post has been updated to reflect version 2022.03.15.


Release notes have migrated to here. You can find prior release notes before v12021.12.22 here.

How to use

To use FirefoxSidebar you will need to clone this repo into your firefox profile as the chrome folder and then follow the Sideberry section below. Both are outlined below in how to do so.

1. userChrome.css

Follow the instructions for adding this repository to your Firefox Profile.

  1. Navigate to about:profiles in your address bar
  2. Click on the 'open root folder` button for your current profile
  3. Open this folder in your terminal
  4. Clone this repo with the following command:
git clone https://github.com/drannex42/FirefoxSidebar.git "chrome"`
  1. In Firefox navigate to about:config in your address bar
  2. change the characteristic toolkit.legacyUserProfileCustomizations.stylesheets to true
  3. Restart Firefox

You could skip the clone step entirely if you manually add the FirefoxSidebar files to the "chrome" folder in your Firefox Profile (you will need to make a chrome folder if it doesn't exist!).

Visit userchrome.org if you are confused or have any questions.

2. Sideberry

Load the sideberry-data.json file into your Sideberry addon by using the 'import' section under 'Help'.

If you dislike any of the theme presets for dark or light themes, or you have a particular color scheme in mind then navigate to Sideberry Settings > Style Editor (found at the end of the settings sidebar). The preference is to replace the values in the right panel, not in the theme editor to the left - this way you can easily update to newer versions in the future.


All extensions can be found in /extensions.

In version 2022.02.23 we broke up the components into extensions using css imports. This makes adding and removing features incredibly easy.

The following extensions are added:

  • [Window Controls / Client Side Decorations (CSD)
    • This adds the window controls to be inline with your address bar.
  • [Superbox Removal
    • This removes the superbox and fixes the address bar padding.
  • [Bookmark Arrows]
    • This adds a nice little arrow next to your bookmark folders.

User Settings

Please backup the prefs.css and the custom.css files before updating to a new versionof FirefoxSidebar. There may be new additions to these files, so you will need to re-add your preferencess to the file accordingly. These files should be updated far less than the other files, but just to make sure please save them.


There are a number of preferences you can enable or disable in the prefs.css file. There are examples and descriptions of the different preferences within that file.

Custom Tweaks

For ease of use I suggest using the custom.css file to for your personal tweaks.

If you use FF without the bookmarks bar

Then the sidebar switcher will be missing, edit custom.css and uncomment the relevant section.

TreeStyleTabs (Legacy)

Either add the firefox/treestyletabs.css to your TST addon preferences or import the treestyletabs-*.json preferences to your TST addon (prefered)