Popular Firefox add-ons and their current multi-process compatibility state

Martin Brinkmann
Nov 28, 2014

Mozilla is working on Firefox's multi-process architecture that it calls e10s and interested users can enable it in some versions of Firefox already.

If you have tried it already you may have noticed that some sites or add-ons that you are using are not working properly when e10s is enabled in the browser.

If you are interested in the progress that is being made in regards to add-ons, then you may want to head over to the Are we e10s yet website which lists popular add-ons for Firefox and their compatibility state.

There you find listed HTTPS Everywhere for example which is listed as not compatible right now. Each add-on that is not working at all or only partially has a bug assigned to it that is used to keep track of its compatibility progress.

For HTTPS Everywhere it is this bug on Bugzilla@Mozilla that you can use to keep track of the issue.

The Electronic Frontier Foundation has just released a new development build of HTTPS Everywhere for Firefox, HTTPS Everywhere 5.0 Development 1 which is e10s compatible.

Firefox users who use e10s and HTTPS Everywhere can use this build to use both together.

Note though that you are running a development version of Firefox if you use e10s already and a development build of an add-on. There is no guarantee yet that everything will work fine at this point.

HTTPS Everywhere is not the only extension that is listed as not compatible right now. If you go through the list you find a massive amount of add-ons that don't work yet including the following ones:

  • All in One Sidebar, no sidebars are being displayed when e10s is active. Unknown status.
  • Ghostery, visualizes web trackers. Unknown status.
  • Greasemonkey, a popular program to load JavaScript on load. Is being worked.
  • KeeFox, a password manager for KeePass. Unknown status.
  • LastPass, the popular online password manager. Work will begin when e10s hits beta according to support.
  • Lazarus Form Recovery, saves web forms so that the information can be restored. Unknown status.
  • Multi Links, a mass link opener. Unknown status.
  • NoScript, a script blocker that is highly popular is not fully compatible yet. The author is working on it though.
  • RefControl, referrer control add-on. Status unknown, appears abandoned.
  • Remove it Permanently, removes elements on web pages. Unknown status.
  • Scriptish, a Greasemonkey alternative. Unknown status.
  • Self-Destructing Cookies, a cookie management add-on. Analyzed currently.

This is just a small selection of add-ons that don't work at all or only partially if e10s is enabled in Firefox. Mozilla seems to have contacted authors of said add-ons and while that may work for some, it won't work at all for abandoned add-ons for obvious reasons.

There is still -- some -- time left and it is very likely that many of the extensions listed as partially compatible or incompatible will become compatible before e10s lands in Firefox Stable.

On a personal note, I had to disable e10s in Firefox Nightly recently as I ran into a series of issues that made the browser unusable for me.

Now You: Have you tried the multi-process feature yet? If so, what is your take on it?

Popular Firefox add-ons and their current multi-process compatibility state
Article Name
Popular Firefox add-ons and their current multi-process compatibility state
A look at some of the add-ons that are not yet compatible with Firefox's multi-process architecture and their status.

Tutorials & Tips

Previous Post: «
Next Post: «


  1. Alex said on November 29, 2014 at 8:42 am

    I really think that e10s will still last to reach stable Firefox. Until everything works fine it will continue in nightly

    1. Pierre said on November 29, 2014 at 6:39 pm

      Currently, E10S has no effect.

  2. city_zen said on November 29, 2014 at 6:30 am

    Martin, do you have any idea if Thunderbird will become multi-process too?

    1. Pierre said on November 29, 2014 at 6:39 pm

      I think not. Thunderbird will no longer have evolutions. Few people use it and it doesn’t have the same importance as FF

    2. Martin Brinkmann said on November 29, 2014 at 8:36 am

      I have not heard anything of it.

  3. Dan said on November 29, 2014 at 2:21 am

    Hmmm. Wondering if Pale Moon will go the e10 route. That’s my browser of choice since Australis.

  4. Karl said on November 29, 2014 at 1:41 am

    Great, first I dodged the Australis bullet and now this! Hope devs can update before this mess!

  5. Ken Saunders said on November 29, 2014 at 1:27 am

    I have no need for a multi-process Firefox and I don’t want it though I guess that it’s inevitable.
    I don’t have performance, stability, or any other issues with it.
    I only have issues with Facebook occasionally and I don’t blame Firefox, I blame Facebook devs.

    1. Pants said on November 29, 2014 at 2:13 am

      FB (and amazon) pages are resource hogs in my experience. Any amazon page load spikes my PC temp up 10 degrees C. FB, not so much.

  6. pschroeter said on November 28, 2014 at 8:17 pm

    What the heck is e10s why would I want it?

    1. Martin Brinkmann said on November 28, 2014 at 8:27 pm

      Quoted from here: https://www.ghacks.net/2013/04/17/mozilla-may-bring-the-multi-process-architecture-electrolysis-e10s-back-from-the-dead/

      So what are the goals of the e10s project? To increase the browser’s responsiveness and stability, and also increase its performance especially on multi-core computer systems. Sandboxing does not seem to be high up the list, but it is listed as a future goal on the Electrolysis page on the wiki.

  7. Tom Hawack said on November 28, 2014 at 7:51 pm

    With all the add-ons, among which major ones — at this time, with their current build, and e10 as it at this stage — I don’t perceive how I would be able to carry on with this new multi-process architecture.

    As always, add-ons bring the taste to a browser but their compatibility issues as well. One thing for sure here is that I won’t abandon an add-on I consider necessary or even most helpful for the sake of a slight velocity improvement.

  8. Dwight Stegall said on November 28, 2014 at 6:25 pm

    I was told HTTPS Everywhere isn’t necessary anymore. That capability is supposedly built into Firefox now.

    1. MS Anti-Fanboi No.1 said on November 29, 2014 at 2:45 am

      You were told wrong. It’s totally not built in.

  9. Nebulus said on November 28, 2014 at 6:04 pm

    Apparently because a lot of users requested it. And of course, Chrome has it so this is supposed to be reason enough…

  10. Kulm said on November 28, 2014 at 5:42 pm

    Great. What a pain in the ass.
    Can someone explain why
    FF feels this change is necessary?

    1. Caspy7 said on November 29, 2014 at 1:55 am

      One of the most common reasons people cite for using Chrome is that it’s faster than Firefox. With javascript speeds now equivalent, this isn’t strictly the case, but it certainly can feel faster because it’s more responsive. In Chrome the main browser interface and the tabs (at varying degrees) are in separate processes which generally prevents one tab from affecting performance of other tabs (or affecting the browser at large).
      Mozilla has gone after preventing “jank” (skitters, pauses, stops) in the UI as much as possible in the single-threaded approach Firefox currently uses, but that still hasn’t defeated some of the fundamental causes which the multi-process approach should.
      As others have mentioned, there are security benefits to be had as well, but that’s not exactly a “felt need” from most consumers’ viewpoints.

    2. XenoSilvano said on November 29, 2014 at 12:02 am

      having each tab running as its own process prevents the whole browser from being compremised due to one faulty tab.

      Aside from Tor integration into Firefox (and possibly among othere things as well) this is a feature that I am looking forward to.

      1. XenoSilvano said on November 29, 2014 at 12:12 am

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.