Mozilla released a Firefox Nightly test build with vertical tabs

Martin Brinkmann
Apr 2, 2024

Mozilla released a Firefox Nightly test build recently that includes support for vertical tabs. This new functionality is not available in regular Firefox Nightly builds, but there is a way to get that build and test it for yourself.

Native vertical tabs support is a highly requested feature. It is placed third currently on Mozilla's Connect website, just behind native tab grouping, and the restoration of PWA support in Firefox.

Vertical tabs move tabs from a horizontal bar at the top of the browser to the side. It enables better drag & drop support, sorting, hierarchical views, and better use of space on widescreen monitors or sites that limit their width.

Firefox would not be the first browser to support vertical tabs. Several browsers, including Microsoft Edge, Brave, or Vivaldi, support vertical tabs already (with Vivaldi taking the cake when it comes to customization options).

There has always been talk about introducing vertical tabs in Firefox. The last time was in February 2022, when Mozilla looked into the matter.

Vertical tabs in Firefox Nightly

The test build shows the horizontal tab bar and the sidebar at the same time by default. A click on the new "hide tab strip" button hides the horizontal tab bar so that only the vertical sidebar remains.

It shows icons only by default in its collapsed state. A click on the expand icon displays labels next to the icons. A lot is going on here, as Mozilla put open tabs next to other actions and options in the sidebar.

The first two options are AI integrations, the third a link to the Side View extensions. This adds a mobile view of a webpage to the sidebar, similarly to how Vivaldi handles this natively. There is also an option to add a new shortcut. This pins the active page to the position on the sidebar.

Open webpages are listed in the next section. You can switch between open tabs, right-click on tabs to display the full tabs menu, or open new tabs with a click on the button.

A third section with additional links is attached to the bottom of the sidebar. Many items cannot be modified or removed at this point. It is okay for a test build, considering that Mozilla's main focus was probably the core implementation and not customization options.

Some keyboard shortcuts work. You can press Ctrl-T to open a new tab or Ctrl-W to close the active tab. Ctrl-R reloads the active page.

The implementation needs polishing, but that is to be expected at this stage. It worked really well during tests. If you want to test it yourself, head over to the Mozilla FTP site and download the version to your system.

Still unclear if Mozilla is going forward

Bad news is that it is not clear at this point whether Mozilla is going to go forward with the implementation. A post on Reddit by one of the project members suggests that the build is a "rough proof-of-concept". Some features tested in the build "did not survive". It is unclear which did not, as they are not mentioned.

Mozilla is, however, implementing those that survived the cut into Firefox. Again, the poster does not mention which those are. It is also not verified that the poster is actually a member of the project team, so take this with a grain of salt as well.

Closing Words

Is Firefox going to get vertical tabs support in the near future? It is possible, but expect tab groups to make an appearance in stable Firefox first before that is potentially going to happen. Still, it is good to see that Mozilla is finally adding requested features to the browser.

How do you like your tabs? Vertical or horizontal?

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Mozilla released a Firefox Nightly test build with vertical tabs
Mozilla released a standalone Firefox Nightly test build recently that includes support for vertical tabs. Here is how it looks.
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  1. hai said on May 1, 2024 at 4:28 am

    I open lots of tabs, native vertical tabs make sense to me. I use Tree Style Tab and love it so much that I can not live without. Here is what like and see some limitation:

    Pros: its tree style means that I can collapse a bunch of tabs. Not like Edge vertical it’s flat structure.

    – it’s an extension. It’s not as stable as native stuff.
    – I have a tree tab bar and horizontal at the same time. CSS can hide it but always wants to keep the native visually

  2. Firefox said on April 7, 2024 at 9:17 pm
    1. Tom Hawack said on April 8, 2024 at 12:29 pm

      Trinity College in Dublin, indeed as it seems :
      “The Long Room Of The Old Library At Trinity College, Dublin, Ireland”

      1. Firefox said on April 11, 2024 at 6:27 pm

        Thank you Tom Hawack.

  3. Tim said on April 6, 2024 at 8:21 am

    We will have more options to choose from, why complain? Some of us prefer horizontal tabs, some vertical ones, let everyone have what they want.

  4. said on April 4, 2024 at 9:11 pm

    From my point of view, the launch of vertical tabs for Mozilla Firefox it’s not mandatory, had seen there to be extensions that attend this demand for those wishing for; continuing with browser original idea of be a flexible, community oriented, browser.

    I particularly, would be more satisfied with the launch of a side tab (or, at least, an update of that poorly made thing of Crtl-b tab) in which thing like extensions features turned on could be save as favorite icons and easy accessible, for example; or web sites like whatapp web, chatgpt and spotify could be saved for quick access. In the manner edge has been doing now.

    In a nutshell, I thing focus more in productivity and fluidity at navigate in web should be the priority, though a sense of organization and cleaness are not totally dispensable

  5. mysiak said on April 4, 2024 at 1:39 pm
  6. Sebas said on April 4, 2024 at 9:45 am

    I do not like vertical tabs, they are in the way of my screen estate size. I really like the classic menu tabs, plus the handling of bookmarks is much better than in Edge. You can arrange all your bookmarks under the menu tab bookmarks which I find excellent.

    1. Pierre said on April 4, 2024 at 4:46 pm

      I don’t like either

      1. Amonymous said on April 6, 2024 at 6:47 pm

        Yet enough do like it for it to be highly requested.

        Choice is good.

  7. Yuri Khan said on April 3, 2024 at 6:06 am

    I basically use my monitor as two 8:9 screens via a tiling window manager so I can’t afford sidebars. For me it’s horizontal multirow tab bar.

  8. Violetmoon said on April 3, 2024 at 1:40 am

    Funny, the first screenshot in this article looks nearly identical to the current Task Manager style in Windows 11–could be identical.

    An earlier article detailed how users who didn’t like the “side” panel style could return to “legacy” tabs at the top, “the classic menu bar” at the top.

    Apparently, users didn’t like the “side” panel style, so now they flock to an easy method of returning to tabs on top.

    Mozilla had tabs on top, but users wanted tabs on the side [Sideberry works well for that]. In fact, Mozilla won’t be able to compete with the features Sideberry offers.

    I do understand–for some or all or maybe one window in the Windows OS, users want tabs on top–some classic menu style.

    The browser preference, across the board, is tabs on the side–left? right?–doesn’t matter?

    I use my left hand for the mouse, so the last place I want tabs is on the left side of my screen.

  9. Anonymous said on April 2, 2024 at 11:51 pm

    FINALLY! This was my last blocker to switch back to Firefox. I’ve gotten so much used to vertical tabs in Brave, especially since I have an ultrawide monitor, where vertical space is much less, than horizontal space.
    I’ve tried to switch back using vertical tab extensions, it’s just not the same as a native implementation.

  10. Scroogled said on April 2, 2024 at 11:05 pm

    Vertical tabs make no sense because it uses more space in your viewing area.

    1. Anonymous said on April 3, 2024 at 7:02 am

      Except if you have more horizontal space, instead of vertical space, like on an ultrawide monitor.

      I’ll say having options are good.

  11. Amonymous said on April 2, 2024 at 7:49 pm

    Man if this is good and actually survives to release I’m going to move back to it from Edge. Vertical tabs is just way too good to give up and the hacky solutions using extensions and CSS just isnt’t great to use on Firefox. Meanwhile Vivaldi vertical tab CSS keeps breaking due to browser updates.

  12. John G. said on April 2, 2024 at 6:10 pm

    I dislike vertical tabs a lot. Thanks for the article! :]

  13. Dave said on April 2, 2024 at 6:08 pm

    No, just no.

    1. Tony said on April 2, 2024 at 7:21 pm

      I used to be that way, but once I tried it (a second time), I don’t want to go back. With all the bloat that the browsers cram up top, it’s nice to have the tabs on the side.

      … and as Martin says “Native vertical tabs support is a highly requested feature.”

  14. HorzPref said on April 2, 2024 at 6:00 pm

    Tab Orientation depends is a preference…

    From my experience it depends on screen resolution and aspect ratio…

    Above a certain point “vertical tabs” are “easier” (after 18+ months of using a “wide” screen)

  15. Mystique said on April 2, 2024 at 5:37 pm

    I prefer horizontal even on a laptop but am not averse to having an option as seen in the latest Waterfox where you can have horizontal tabs but if you press the button to make the tabs appear vertically then the horizontal ones become hidden and everything adjusts to vertical. They only implemented it fairly recently so it will improve over time but it seems okay right now.

    The Visual Tabs extensions offer the ability to navigate tabs vertically when called upon whilst simultaneously allowing you to keep the horizontal tabs too. It’s great for finding tabs but given that there is meant to be tab previews now on the tab bar it probably has limited use for me now. Coincidentally the developer or Visual Tabs is the very same person that brought us Tab Scope many years ago. I can’t really get Tab previews to work on my Waterfox just yet but for now things are fine.

    At least Mozilla are listening. I had seen so many comments regarding vertical tabs when things hit the fan with Chrome and then also the youtube fiasco but more so the web environment stuff.
    Who knows but I guess this is a good thing for those people.
    Maybe we can get that more robust and powerful implementation of web extensions that they promised. lol hahaha.

  16. InsaRata said on April 2, 2024 at 4:37 pm

    never understood all this necessity having the tabs vertically

    1. Amonymous said on April 2, 2024 at 7:55 pm

      Compressed horizontal tabs sucks, especially if you have a lot of tabs from the same websites. It’s why I stick around with Firefox until Edge introduces Vertical Tab into the browser itself. At least for me, Vertical tab is basically the advantages of compressed tab combined with full tab title view of uncompressed one like from Firefox.

      If Firefox can introduce this officially, I’m definitely moving back. I miss dedicated search bar (for anyone saying to use Vivaldi for the search bar, the vertical tab CSS keeps breaking due to new browser updates).

  17. Paul(us) said on April 2, 2024 at 4:19 pm

    I still have a preference for the horizontal way, perhaps because it is what I am accustomed to.
    Young people who are using the browser for the first time may have a much more fresher point of view.

    I have tried Brave and Vivaldi to see the benefits of a vertical tab bar.
    I have not found that it works for me to enable better drag-and-drop support, sorting, hierarchical views, and better use of space on widescreen monitors or sites that limit their width.

    I’ve got a couple of widescreen monitors, but I like more screen space above the vertical tab bar because I noticed that it’s much more distracting to me.

    1. Amonymous said on April 2, 2024 at 7:50 pm

      I use the internet since the 90s and finds vertical tabs to be great. So it’s just different preference, not age.

  18. Tony said on April 2, 2024 at 3:54 pm

    I like the implementation personally, but it definitely needs to be able to remove some elements. Bitwarden gets stuck on the bar for no reason and can’t be removed.

    However, the tab card preview works with this implementation, whereas it does not work with CSS versions of vertical tabs, which brings it in-line with Brave. I like that a lot.

    Martin, regarding the “test build” remark, I downloaded Nightly from the standard Nightly link and I have the feature. I’m not sure if that counts as your “test build”, but I did nothing special to get it.

    …it is odd that Mozilla is silent on this feature though.

  19. Tom Hawack said on April 2, 2024 at 1:39 pm

    Great of course for vertical tabs aficionados of which I am definitely not.

    Side-note : could anyone grab me the first book from the top-left as seen on the article’s screenshot? Thanks :=) Nice pic, Martin.

    1. Martin Brinkmann said on April 2, 2024 at 1:47 pm

      Thanks ;)

      I do prefer horizontal as well. Main reason is that I display two webpages side-by-side all the time on my desktop. That does not work so well with vertical tabs, especially on the second window.

      1. Mystique said on April 2, 2024 at 5:21 pm

        I miss the days when extensions were more powerful and tile tabs was not trash. I can still miss that extension. I am aware the extension has been ported but its only a port by name not it abilities or capabilities.

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