Add-on Compatibility for Firefox 29

Firefox 29 will be released on April 29th. Here’s the list of changes that went into this version that can affect add-on compatibility. There is more information available in Firefox 29 for Developers, so you should read that too.


This is an actual movie

Yes, this is a joke.

This is a big one. The Australis theme introduces major changes that all add-on developers should be aware of, but it’s nowhere nearly as dramatic as initially thought. We’ve already been blogging about it extensively, so please give these articles a read if you haven’t already:

Notable changes include the removal of the add-on bar and the Firefox button on Windows, the introduction of the menu panel, and an overhaul in the toolbar customization system. Toolbars are no longer hidden for about: pages, there’s no small/large button setting anymore, and tabs are always on top.

Make sure you test your add-on extensively, paying special attention to button customization.

If you notice any problems in your add-ons related to Australis, please file a bug and add it as a dependency to one of these bugs:

  • Add-on issues. This is for add-ons that haven’t been updated yet and are visually broken in Firefox 29 and above.
  • Australis add-on bugs. Use this one if something is broken in your add-on and you believe it’s a bug in the new code.




Please let me know in the comments if there’s anything missing or incorrect on these lists. If your add-on breaks on Firefox 29, I’d like to know.

The automatic compatibility validation and upgrade for add-ons on AMO will happen soon, so keep an eye on your email if you have an add-on listed on our site with its compatibility set to Firefox 28.

23 comments on “Add-on Compatibility for Firefox 29”

  1. Peter Liljenberg wrote on

    Here’s another new SDK feature that’s supposed to be included in Firefox 29: context menu item visibility can now be controlled from the add-on script using PredicateContext.



    1. Jorge Villalobos wrote on


      1. Dick Tripp wrote on

        I like the add on bar and will revert to version 28 regardless of the degraded safety. Firesizer is important to me and it will not work without the add on bar at the bottom of the window. Goddamnit!!

        1. Jorge Villalobos wrote on

          As the Firesizer developer has pointed out, you can install an extension called The Add-on Bar to restore the add-on bar and go back to the way things worked on 28.

  2. Brian P wrote on

    It looks like according to bug 952602 that disabling enumerating navigator.plugins was pushed back due to regressions.

    “Firefox 28 has now shipped, but this feature is not ready to ship with Firefox 29. I would now like to land this patch on all channels (Nightly 31, Aurora 30, and Beta 29) until I have a complete solution for regressions from this plugin detection change.” Which that did land on all three levels.

    One regression would be:
    “the current plugincheck site will continue to work correctly with the current and future Firefox release and “late Beta” channels. Only the Nightly, Aurora, and “early Beta” channels will be affected by the plugin enumeration changes.”

  3. Ken Saunders wrote on

    The graphic is hilarious. 🙂
    It should be shared with SUMO since they’re going to catch the brunt of things.

  4. Kohei Yoshino wrote on

    Bug 757726 – disallow enumeration of navigator.plugins

    This has been disabled in Firefox 29, 30 and 31. I have updated the flags in the bug.

  5. Kohei Yoshino wrote on

    And the Japanese translation is available at

    1. Jorge Villalobos wrote on

      What would I do without you 🙂

  6. MattN wrote on

    One of the changes that affects most extensions with toolbar buttons is the larger icons that are needed when the button is placed in the new menu panel or the customization palette. This is mentioned on but I think it needs more attention as even many of the top 10 extensions have blurry scaled icons.
    The icons should be 32px (or 64px with 2dppx displays):
    “Menu panel/Customization area (palette):
    Please note that smaller icons will be upscaled…”

  7. Esther wrote on

    update automatically java and add ons , dont block that

  8. Kenr L. Schepler wrote on

    How can I go back to version 27 or 28?

    1. Sasparilla wrote on

      Go to Firefox Extended Support Release – its using Firefox 24 but continuing security updates till Firefox 31 is released (at that point it’ll roll over to that). You can find it here:

  9. Marc wrote on

    I had a new version of my add-on in the review queue, when I upgraded to 29 I noticed it wasn’t working. I haven’t had time to figure out where the bug is yet but I wanted to make sure the new version didn’t get reviewed until I did, so I disabled that version. Is that the right thing to have done? Is there a way to re-enable it or do I just have to re-upload with a new version number once the bug is fixed?

    1. Jorge Villalobos wrote on

      I think it’s okay to do that if you think it’s better to give users the fully-fixed version when it’s ready. You’ll need to upload a new version with a new version number when you have it ready for review.

    2. rick wrote on

      please for the love of God someone answer this man as i just want to go back to 28 too.
      I did NOT download the damn new one as it looks hideous, I’m 50 adn DO NOT WANT TO LEARN ANYTHING ELSE RELATED TO DAMN COMPUTERS.
      Just help me go back to the 28 I had when I went to bed; please.

  10. drbits wrote on

    Removing the title-bar in Windows is an atrocious breach of trust with users. Fortunately, it can be restored in “Customize”. However, the default Must be title-bar=visible in desktop versions of Windows. Touch panels (especially mini-tablets and phones) running Windows RT should default to title-bar=invisible.

    The problem is that in Desktop Windows 7+, the minimize and maximize options have been removed from the Windows Taskbar. These are only available in the title-bar. They were removed, because Micro$oft assumes that clicking on the taskbar button for an application will minimize a window or that users will use Alt+Tab in Windows 7 or the start page in Windows 8. Many users have not figured out how to do this. Minimizing by clicking on the taskbar button does not work correctly when there are many programs running.

  11. Gilmar S. MARTINS wrote on

    Hello Jorge, hello all,

    I like Firefox (using it for +5 years) but I don’t appreciate at all that upgrading to FF29 changes my previous settings without asking anything.

    It’s very very VERY bad idea. New versions should never change the previous settings without appropriate warnings because it just leads to a WASTE OF TIME.

    So, I like FF but I don’t want it to waste my time. Thank you for your attention and all you’ve been doing to have this great browser. But don’t forget : make people waste time is not a good idea.



  12. creed3 wrote on

    I agree with Gilmar. For what ever reason FF just decided (against my wishes) to ram an update down my throat and changed EVERYTHING. In all seriousness, what is wrong with you people? The one main reason I used FF is because i could get the damn tabs off the top of the browser window (which makes no logical sense to me) and now I’m forced into this crap? My themes are all gone because someone at Mozilla decided I would like this new one better? Seriously? I may as well join the masses and switch to chrome. Wake up folks. Extensibility is the reason so many of us have stayed with FF from the beginning. What seems like a ‘new & better’ way to you most certainly is not for many of us. If you want to kill your browser, just do it rather than slowly make us hate it.

  13. Sasparilla wrote on

    This is more of a user observation, so sorry if this isn’t appropriate. I noticed that Firefox 29 doesn’t play Apple’s recent WWDC through its Quicktime plugin (latest version in Windows), stalls out on initial loading, but with Firefox ESR (which was 24) it plays fine.

  14. ILEANA CABANAS wrote on


  15. fixitmanarizona wrote on

    Enough with having add-on developers “fix” their add-ons so they work with a new version. MAKE THE new version of Firefox COMPATIBLE with old add-ons. Don’t release a new version until they are. If that takes five years, all the better. No more upsetting version changes every time you turn around, that change the way you have to work.
    I have it.. Let’s move the steering wheel to the tailpipe, so you have to GET OUT OF THE CAR and SUCK HOT EXHAUST to steer. That’s what all these changes equate to, for me.
    I’m sticking with FFx 24 which I JUST finally was able to customize to suit me. If you want to release version 54, make sure it’s backward compatible with version 24, and my customizations including the exact way it looks, DO NOT get lost, and works the same, or there’s no reason for me to “upgrade.”
    Just provide the security fixes without changing the way it works, looks, or “feels.”
    Thank you.

    1. Joe wrote on

      A lot of users are considering either a fork or moving to something like SeaMonkey. Not having freedom for minorities (which add up overall to the majority) kind of defeats the purpose of Firefox. If I wanted a browser that ‘just works’ and is practically idiot-proof, I’d choose Chrome. It’s simple math: People use Firefox for when Chrome is too stupid to let you do what you want. They talk about ‘edge cases’ and how it only gets a few loud complainers, but then forget that there’s literally hundreds of possible edge cases that add up to quit a large percentage of their userbase. Besides, it’s not the total number of users that matters but how useful it is to the ones that _do_ use it.