Firefox Quantum (ver >= 57) - How Can I Hide the Horizontal Tab Bar with TreeStyle Tabs?

The horizontal tab bar can be hidden with the following steps:

Confirm or Create:

Linux: ~/.mozilla/firefox/<profile name>/chrome/userChrome.css
Windows: %AppData%\Mozilla\Firefox\Profiles\<profile name>\chrome\userChrome.css
macOS: ~/Library/Application Support/Firefox/Profiles/<profile name>/chrome/userChrome.css

Add the Following code to: userChrome.css
```
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
#TabsToolbar {
    visibility: collapse !important;
}
```
^Note: Line 1 is required when creating the file and does not need to be included more than once.
Restart Firefox

As this is a custom workaround until either Firefox itself allows the horizontal tab bar to be hidden, or the TreeStyle Tabs extension itself hides it, this information may become dated in the future.

Confirmed Testing: Firefox Nightly 58.0a1 (2017-10-23) (64-bit)

EDIT: Added macOS. h/t: @coderuby

semtex41

Posted 2017-10-23T16:19:35.287

Reputation: 945

Worked for me on 57.0b12, 64-bit -- thanks – JJohnston2 – 2017-10-30T01:30:09.960

Confirmed working on 57.0 64-bit, Linux Mint. – David Heyman – 2017-11-14T23:03:39.610

1Works on macOS 10.11.6 with Firefox 58.0b4. On macOS the userChrome.css can be found or created under: ~/Library/Application Support/Firefox/Profiles/<profile name>/chrome/userChrome.css – coderuby – 2017-11-16T09:44:40.900

Note: if you open a new window, you'll still have to click the Tree Style Tab button if you open new tabs. Otherwise they'll be open, but hidden. – Anssssss – 2017-11-16T20:41:39.433

@Anssssss There is a plugin hotkey of F1 that toggles the sidebar. Details can be found in the description (at least as of ver 2.2.9 of Tree Style Tab) – semtex41 – 2017-11-17T06:48:54.403

4Users who view issue this may also want to hide the Tree Style Tabs heading that appears in the sidebar: #sidebar-header { display: none; } – uglycoyote – 2017-12-14T17:19:21.300

1just FYI. I did not have a chrome folder there neither userChrome.css file! Had to create it, but it works. – Vitas – 2018-01-11T20:27:18.567

I put it here: AppData\Roaming\Mozilla\Firefox\Profiles\d0blabla\chrome Note the "Roaming". There is also an up-to-date mozilla dir tree under "appData/local" but that did not work. – David Lotts – 2018-04-18T20:10:03.360

This is still needed and still works in 65.0a1 (2018-10-30) (64-bit). – daveloyall – 2018-11-01T18:06:23.890

This solution also works for Tab Center Redux. – Raptor007 – 2018-12-25T11:09:15.953

Firefox Quantum (ver >= 57) - How Can I Hide the Horizontal Tab Bar with TreeStyle Tabs?

Answers