Firefox 3.6 Beta 1 review

Firefox 3.6 Beta 1 is now available for download!

Before starting the review, keep in mind that Firefox 3.6 will be the smallest upgrade Mozilla has released to date. Before this, version jumps have been in the 0.5 (Firefox 1.0 to 1.5, 3.0 to 3.5) or 1.0 (2.0 to 3.0) order, and while version numbers are not mathematically representative, the slight 0.1 version increase reflects the overall tone of this update, and Firefox development in general which is moving to a faster release pace.


Without a doubt, the most significant addition is support for lightweight themes, also known as personas, that was previously only available with the Personas extension.

A persona, which consists of a couple of images used as backgrounds for the toolbar and status bar areas, and setting a text color, is very simple to author, yet it significantly changes the appearance of Firefox and becomes a way of expression for the user.

To try it, simply visit Mozilla Add-ons, and go to the recently added Personas section. Personas are live previewed as you hover on the thumbnails, and become permanent when you click on Wear It.

Themes after all, personas are also managed via the Themes page in the Add-ons Manager.


Tabbed browsing

Firefox has finally got tab preview, though it’s turned off by default. To activate it, you must set browser.ctrlTab.previews to true via about:config. After that, when you press Ctrl + Tab to switch tabs, you get a horizontal line of tab thumbnails.

Ctrl tab preview

You can also press Ctrl + Shift + Tab to get a preview of all currently loaded tabs, and even search the tabs’ titles which comes very handy when having more than 20 or so at a time.

All tabs preview


A couple of special about: pages have been added. about:support, should become a troubled user’s best friend as it provides a helpful page with most details of your current Firefox settings including version number, customized preferences, and installed extensions; all of which can be easily copied to a support forum, email or chat window.


about:memory, is a first try on providing details about the current Firefox memory consumption.



Native videos now have a full screen option: right click on a video and select Full screen. On related news, a new full screen button is now available to add to the toolbars.

Video full screen

Tabs opened from a page (like when middle-clicking on a link) now open to the right of the current tab making it easier to reach content that we know is related to what we’re currently on.

A small but significant change: if you attempt to launch Firefox while only non content windows are open (like the Add-ons or Downloads Manager), Firefox won’t create a new window as before but restore the last closed window.

Autocomplete suggestions in previously filled web forms are now sorted by frecency, a combined indicator that tells how frequently and how recently an option was used. A nice addition useful in very particular cases though.


As announced before, Mozilla is now supporting the Web Open Font Format (WOFF) which has the advantages of smaller size thanks to compression, and the ability to trace the source of a specific font without the burden of DRM.

TraceMonkey, the JavaScript just-in-time optimization technology introduces with Firefox 3.5 is now also enabled by default for the user interface, which relies on JavaScript for much of its functionality as well.

Finally, this beta introduces support for the new Windows 7’s taskbar previews feature. Don’t get too attached to it though, as it is buggy right now and may be pulled back depending on how it evolves in the next few days.


Further Windows 7 integration like showing a download progress bar in the taskbar and jump lists are also in the works but unlikely to be ready for Firefox 3.6.

The current nightlies are labeled pre 3.6 beta 2 suggesting a second beta may be the next step. This would be in line with the latest roadmap.

Not much is left for future development releases. One final feature could be per tab network prioritization which will make Firefox allocate more bandwidth for the currently viewed tab, less for other tabs in the current window and even less for other windows, enhancing the perceived responsiveness.

As usual, a critical subject are add-ons. Right now about half of them have been updated to some 3.6 development release. You can help increase this number by installing the Add-on Compatibility Reporter. Once installed, all your extensions will be enabled. You can then check and see if they work or not, then go to the Add-ons Manager and report whether it works or not.

Add-on Compatibility Report

18 thoughts on “Firefox 3.6 Beta 1 review”

  1. Also added in 3.6 is the new “Find Updates” button for plugins in the Add-ons Manager which takes you to the plugin check page. There’s also support here to announce plugin updates through the manager and take users to this page automatically as needed in the future.

      1. pjd, no, you’re thinking about extensions and themes. The Add-ons Manager has of course had a “Find Updates” button for them for quite some time. Plugins, on the other hand, currently don’t have that button and are wholly left to their own devices. In Firefox 3.6 this class of add-ons finally gets its own update checking mechanism, half of which is:

  2. I’ve downloaded Firefox 3.6b1, but have not had a chance to try out yet. Being ‘smallest upgrade’ sure seems to pack a lot of new features. I love that Persona is now integrated into Firefox now.

  3. Thanks for the review, Percy! As always, I find stuff I didn’t already know about when I read Mozillalinks – even though I obsessively follow planet Mozilla! 🙂

  4. That Add-on tester ended up breaking my add-ons, I had to toggle the compatibility boolean in about:config. Pity, cuz it would be useful for the add-on devs

  5. Will this version enable dragging of addresses straight to the bookmarks toolbar and the left side bookmarks display list. (Sorry do not know correct terminology for that panel).

  6. What about the issue of slow startups. When I say slow I mean approx 45 seconds. My understanding is that firefox examines temp folders during startup. I’m at version 3.5.5 and I still have this issue.

  7. All I care about is Firefox for mac FINALLY HAS FRICKEN FULL SCREEN WOOT!!!!!!!!! Also, pretty damn happy about the whole stability thing ;P

  8. For those who may still be looking for the answer to Jim’s question above … does version 3.6 improve the slow startup speed many people found with 3.5, the following review says yes:

    “Firefox 3.6 also features improvements to the underlying engine and performance of the Web browser. In initial tests, the speed of the browser—in terms of both start-up time and site browsing performance—was good. In tests performed with the Peacekeeper benchmark, Firefox 3.6 showed notable improvement over Version 3.5 of the browser”

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