Mozilla experimenting with vertical tabs

Martin Brinkmann
Sep 13, 2012
Updated • Sep 13, 2012

Firefox users can move browser tabs to a sidebar so that the tabs are displayed vertically with the help of extensions such as Tab Kit. This at first may be confusing to users of the browser who always had their tabs aligned horizontally, but the benefits may make it worth their ewhile. Computer monitors nowadays are often wide screen displays, which means that you get lots of width and not so much height. Websites on the other hand usually limit the width of their contents, so that space remains untapped in the browser if you are running it in fullscreen or a large window.

Moving tabs to the side not only makes available additional vertical space for the actual website, since the tabbar is no longer displayed in its original location, but also additional tabs before you need to start scrolling.

A recent Australis demo document (pdf) highlights that Mozilla seems intent to add vertical tabs as an option in the near future. It needs to be noted that this is a mockup right now and not something that you can activate. Still, it is likely that this feature will eventually make its way into a future Firefox version.

firefox vertical tabs

The mockup demonstrates how vertical or sidebar tabs could look like in the browser. It is interesting to note that tabs are displayed as thumbnail images and page titles here. It is likely that tabs will only be presented this way if they do not exceed a certain threshold, as too many open tabs would either render thumbnails too small or reduce the overview over open tabs as you'd have to scroll a lot as only a certain number of thumbnail tabs fit on the screen at the same time.

If you look closely, you will notice that the mockup showcases a different design than other mockups. This can't be attributed to the moving of the tabbar alone, and is an indication that designs are not final yet either way.

I'd like to see the following features supported if Mozilla implements the vertical tabbar in the Firefox web browser:

  • Options to place the tabbar on the left or right
  • Options to disable thumbnail previews and use text only links
  • Options to modify width, height and font sizes

What's your take on the development? Would you like to see a built-in sidebar tabs in Firefox? (via Sören)

By the way, some of the other sheets of the pdf document linked above show other ideas and mockups that you may want to take a look at. You see the new about:home or new tab page here for instance. One interesting little tidbit here is that one mockup shows weather conditions on the screen. Could this be the integration of a speed dial extension-like feature that Opera supports for a while now?


Tutorials & Tips

Previous Post: «
Next Post: «


  1. Paweł said on April 5, 2013 at 1:22 pm

    How to add a vertical toolbar to Firefox?

  2. Glenn said on October 19, 2012 at 8:24 pm

    Well, [page] tabs *belong* on the right side (just like in the real world), but I’m fairly sure Mozilla will find a way to screw this up, too. As it is, I’ve had my Fx tabs on the right for awhile now–it’s perfect for wide-screen monitors (as you say). It’s now hard for me to imagine them being anywhere else.

  3. Mateusz said on September 15, 2012 at 3:02 am

    Tab Kit: Not available for Firefox 18.0 :((

  4. Stonecold said on September 14, 2012 at 11:34 pm

    I wonder how this’ll work with a lot of tabs open? I currently have 101 tabs open in Chromium, and just earlier today I had 150+ (yeah, I know). The two reasons I haven’t moved to Firefox though is that I’d hate to scroll through so many tabs (I’m use to picking out tabs by their squished icons now) and because Firefox tends to die after about 30 tabs. I bet having the tabs on the side like that would be a huge inconvenience with a lot of tabs.

    1. Martin Brinkmann said on September 14, 2012 at 11:53 pm

      I do not think it is a issue whether tabs are displayed vertically or horizontally performance-wise. You usually can display more tabs vertically, which is a huge advantage over the current implementation. So, in theory at least, you scroll less when you display the same amount of tabs vertically instead of horizontally.

  5. David said on September 14, 2012 at 8:45 am

    Is the same function of Tab Sidebar

  6. senina said on September 14, 2012 at 5:08 am

    Sounds useful for us wide screen users. I like using the split view feature of Avant browser which can display and view two webpages at the same time in my wide screen. From the image, the tabs seems to large… I will try it and see which one is better for me.

  7. Penizzia said on September 13, 2012 at 8:46 pm

    I’ve been using Tree Style Tab for 6 months and never looked back!

  8. Jim said on September 13, 2012 at 7:31 pm

    I don’t have the extra space problem because I don’t run my browser window maximized. I typically have it set up to max top to bottom and 60-70% of the width. That seems to be about right for a 1920×1080 display. This allows me to have other windows open to the side of the browser and see all of them at once. While I can see the advantages of vertical tabs, it wouldn’t do much for me because I don’t keep a lot of tabs open like some folks do. I typically have less than 10 open. (Right now I have 2, both ghacks. ;-)

  9. Transcontinental said on September 13, 2012 at 7:24 pm

    I have a rather conservative attitude when it comes to the layout of applications I use a lot. Not always though. Having the tabs vertically layed out is more than interesting. Count me in for this move. Indeed screen space preoccupation is vertical nowadays.
    I had a look at ‘Tab Kit’ add-on but it is no longer available for latest Firefox version, Firefox 15 anyway, otherwise I’d try it.

  10. Jojo said on September 13, 2012 at 7:16 pm

    Just use auto-hide tabbar from stylish and you maximize your browser space easily. I keep my tabs on the bottom and I show 10 pixels of the top row using this code:

    @namespace url(;

    #main-window .tabbrowser-strip {
    height: 10px !important;
    overflow: hidden !important;

    #main-window .tabbrowser-strip:hover {
    height: 100% !important;

  11. Uhtred said on September 13, 2012 at 6:39 pm

    not so keen on the vertical tabs, but if it does happen, in addition to your suggestions I’d add:

    Option to disable initial display of thumbnails, using favicon for site instead, with mouseover reveal of thumbnail and/or text. This would make it a much narrower option for us small screen users, more resembling a vertical bookmark toolbar.

  12. Praveen said on September 13, 2012 at 5:29 pm

    “but the benefits may make it worse their while”

    1. Martin Brinkmann said on September 13, 2012 at 5:48 pm

      Thanks, it took a moment to find the error.

  13. argo said on September 13, 2012 at 4:11 pm

    urk! just a few century after opera and thousand of extensions doing this! :D … welcome mozilla!

Leave a Reply

Check the box to consent to your data being stored in line with the guidelines set out in our privacy policy

We love comments and welcome thoughtful and civilized discussion. Rudeness and personal attacks will not be tolerated. Please stay on-topic.
Please note that your comment may not appear immediately after you post it.