I had posted earlier on my initial experiences with the Firefox 3 beta inside a sandbox, and decided to hold off on a full time switch to the beta as most of my favourite extensions were incompatible. The incompatibility status for the extensions has not changed, but I discovered an easy workaround (no hacking around xpi) today when looking around for a working mousse gestures extension.
All I had to do was to create a “extensions.checkCompatibility” boolean field in the Firefox about:config and set it to false. As you can guess, this disables the compatibility check for the extensions, and all the disabled incompatible extensions are enabled (with warning messages). Of course, this does not guarantee that the extension will work. Also the browser crashed on the first restart (the subsequent restart was fine though).
However, I was able to get most of the required extensions working this way (not extensively tested). They include Mouse Gestures, del.icio.us bookmarks, Greasemonkey (Update 22/01/2008: Greasemonkey just got an update today and is now supported on Firefox 3 beta), MR Tech Local Install (this one can override extension compatibility versions) and PDF download. Some extensions remain unusable though like Tab Mix Plus (possibly due to the architectural changes) and Google Gears (might be because I’m running inside a sandbox). Not a major loss, though I miss some of the tab tweaks provided by Tab Mix Plus.
I plan to use the beta inside the sandbox as my primary browser now that the extensions problems has been worked around. I’ll post my findings in in a few weeks, by which time some updates are likely to be available.
As for the changes from beta 1 to 2, check out the release notes. Of note is the fact that the rich interfaces of Yahoo Mail and Windows Live Mail are still unsupported.
There seem to be further tweaks to the memory usage (image below) and rendering. The interface hasn’t changed much, though a Smart Bookmarks folder seems to have been added to the bookmarks toolbar. The earlier location bar update that includes suggests autocomplete entries based on the page titles and not just the link text is quite a useful feature.
And to sign off here’s a comparison of the memory usage of v2 (top – gray) vs v3b2 (bottom – blue) with the same 8 tabs open in each, taken using process explorer. Note that there are fewer extensions in v3b2 and it is running in a sandbox.
AB's Reflections 
This is helpful information. Thanks for sharing.
Beta 2 apparently doesn’t have that option in the about:config. Do you know of an equivalent I could use to do that trick? Thanks!
Hi Helder. You need to create the variable in case it is not present. Just open the about:config page in Firefox, right click and create a new boolean variable with the said name and set it to false.
Hi!
First of all thanks for this article!
I’d like to provide additional receipt to turn ON those extensions that left locked even after applying extensions.checkCompatibility.
Here is another one parameter: extensions.checkUpdateSecurity.
Set it to ‘false’ and all of those extensions that has unsecure update URL in section will be unlocked!
Thanks! Gestures was the one thing stopping me from using the FF3 beta full-time 🙂
Nice article. Thanks for sharing.
I tried the hack and most of my extensions now work in FireFox 3
Anyone know how to get “Always Remember Password” to work in
FireFox 3
For all Tab Mix Plus fans out there, there’s a developer version available on the TMP site. I got the link from a comment on the Firefox addon site.
Finally I have my dotComplete extension working on Firefox 3. Thank you.
MR Tech Local Install (now called Toolkit) is now compatible with Firefox 3.
If You can’t wait for extension authors to update… just use this little trick to break/skip extension verification and use any obsolete add-on in FF3 (FF2).
http://www.reeloo.net/wordpress/how-to-manually-update-firefox-xpi-extensions
Actually now that MR Tech Toolkit is Firefox 3 compatible, we don’t need any hacks as it provides a version check override option.
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Hm that sounds good but I would like to know more details.
Your news is a cool stuff man, keep it going.
That’s good man, keep it going.
Good story for me but please more details.
Good information to me.
Stunning blog and good article. High 5 for u man !
This is a very good stuff man. But you can be more specific next time. See ya !
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