After being forced to update to Firefox Quantum, I:

  1. downloaded Firefox 52.9.0 ESR
  2. toggled xpinstall.signatures.required in about:config from true to false

But even when most XUL add-ons work again, in Tree Tab Style and Reddit Enhancement Suite I have this error:

Tree Tab Style error

In previous times when I have to downgrade Firefox, I've never seen this. All I need is to do (2) and all is good. Googling the problem yields no result. How can I fix this?

Unfortunately, not all Firefox addons are supported in Pale Moon. I can't use Waterfox too, because it doesn't support 32-bit machines.

  • hmm, what's wrong with this question? – Ooker Sep 5 '18 at 18:26
  • 3
    @dsstorefile1 IMHO it shouldn't be a reason to downvote question. There a lot of software that still in use even it isn't supported anymore and security concern isn't a question when working environment completely isolated from the rest of the world. Mozilla screwed up a lot of very useful addons when switched to ChromoFox and took out control to manage browser from addons. While it good for general population to not allow control browser completely, they removed most attractive browser's feature - to control browser as advanced user wants and as of today there no alternative but use 52ESR – Alex Sep 5 '18 at 22:05
  • @dsstorefile1 actually it isn't the internet point that concerns me, it's the unexplained downvotes on a question that isn't track of research. The downvoters can easily discuss the importance of having security patch updated in the comment. See more about this frustration – Ooker Sep 10 '18 at 2:18
  • 1
    @dsstorefile1 It isn't my question :) The question is about tech problem. One can inform about security concern as u did (52 ESR stopped receiving security updates), but it isn't a reason to downvote. I just pointed out that there're still a lot of cases when one need/want to use outdated software and they have own opinion and reason to do that. I simply don't understand people who downvoting without leaving any comments. If it would be me, I would require to leave a reason in comments if one want to downvote. – Alex Sep 10 '18 at 20:10
  • 1
    Just FYI, Pale Moon offers a 32 bit version. It will run legacy Firefox add-ons and is supported, so you don't have the risks of continuing to run ESR v52. BTW, you will need to take extraordinary measures to prevent Mozilla from updating ESR v52. As soon as support stopped, mine was updated despite all of the settings no to auto-update. – fixer1234 Sep 12 '18 at 3:00

That's because when Firefox updated it also updated the addons. Later versions of them are simply incompatible with Firefox 52. Visit the old version of Tree Tab Style and RES to install them.


You can't defer upgrades forever. At some point of time Firefox patches from the main branch will also be merged into the long term servicing branch. You'll have to find a fork if you want to continue using XUL add-ons.

Among the forks there's Pale Moon that still has the 32-bit version and the long term plan is to support XUL add-ons forever

Pale Moon supports and will continue to support the following features/technologies:

  • Full UI customization
  • Full theming (complete themes) and lightweight theming (personas)
  • XUL and XBL to build interfaces and applications (including the ability to launch independent XUL-apps from the browser binaries).
  • Full support for NPAPI plug-ins
  • Overlay and bootstrapped (restartless) extensions
  • Access to low-level APIs from extensions, allowing them to truly extend browser functionality, and not just manipulate web content
  • Pale Moon Sync (in the secure, time-tested Weave fashion); it will be able to use any Weave Sync 1.1 compatible server, including some FOSS cloud solutions.

Despite that it has been diverged too long ago, therefore the code is now very much different from the current Firefox. And of course it can't run on multiple CPUs.

The developers of Pale Moon are also developing a new browser named Basilisk based on newer Firefox ESR

A XUL-based web-browser demonstrating the Unified XUL Platform (UXP).

This browser is a close twin to pre-Servo Firefox in how it operates.

However currently it's still in beta stage and not considered stable.

That said, the recommendation is to install a 64-bit OS and use a 64-bit browser. Apart from performance improvements, 64-bit apps have bigger address space, which helps ASLR work more efficiently. On 32-bit OSes once an app uses up to near its maximum 2/3GB of memory, there's no free space for it to move around anymore. That's why Mozilla said that

On the flip side, as well as avoiding address space exhaustion problems, a security feature known as ASLR works much better in 64-bit applications than in 32-bit applications, so 64-bit Firefox will be slightly more secure.

Besides, the latest Pale Moon release note also mentioned

v28.0.1 (2018-08-31)

This is a bugfix point release to address serious performance bottlenecks and general run-time issues (UI slowness, crashes, hangs) with the browser. Once again this impacted 32-bit operating systems more severely than 64-bit ones due to its more limited address space that would get flooded with bogus data.

Similar thing is said from Chromium's team:

Finally, on 64-bit, our defense in depth security mitigations such as Partition Alloc are able to far more effectively defend against vulnerabilities that rely on controlling the memory layout of objects.

Also read You Should Upgrade to 64-bit Chrome. It’s More Secure, Stable, and Speedy

For various other things that make a 64-bit OS generally safer, read is 32-bit safer


As you asked for 32bits you can be interested in following web-browsers (from Fedor2) and specifically in Centaury.

  • Centaury, fork from Basilisk code
  • Mypal, fork from Palemoon code

Centaury/Basilisk, though is not final version it is a very reliable browser which supports modern XUL addons.

I tested both in old hardware and reactOS

releases at github

  • This is really a comment about phuclv's answer rather than a new solution to the question. – fixer1234 Dec 18 '18 at 23:56
  • phuclv's answer was impressive, so i can only add facts from my user experience with Basilisk and information about two forks of recommended webbrowsers which are targeted to win32. (original question made reference to win32) – Daniel Perez Dec 19 '18 at 8:25
  • 1
    With just 6 more rep points, you could post it as a comment on that answer. I commented because you're just 6 pts away, and a "non-answer" could attract downvotes, making it harder to get there. :-) – fixer1234 Dec 19 '18 at 8:51
  • Thanks @fixer1234. I modified the text to focus on the different solution and approach. – Daniel Perez Dec 19 '18 at 11:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.