First look to Firefox 3.5 RC2

Mozilla has released Firefox 3.5 RC2, the second release candidate of the next major Firefox upgrade.

If you’ve been following Firefox 3.5 development you may realize there was no RC1 as expected. In fact, this is a new approach Mozilla is taking for this stage. As explained by Mike Beltzner, Firefox product director,  basically, the first RC (not as thoroughly tested as a public RC but considered safe)  is offered to beta users only so this large audience (around 900K users) can provide feedback while full QA is done on the build. With beta feedback and QA results a second RC is produced, quickly tested (as changes are minimal) and this one is released to the public, which has been the case. In short, RC1 existed but it didn’t make it for public availability.

There is not much new in this candidate. As expected at this stage, work is mostly polishing. In particular, the Windows themes got some update tab scrolling, tab list and new tab icons to better match Windows’ style.


In Linux, there are new icons for blocked plug-ins, while in Mac, the etch was removed from the Back/Forward keyhole shape introduced in Firefox 3.

Also, as unveiled a few days ago, there’s an update to the Firefox icon to reflect the many changes that have happend since it was modified around Firefox 1.5 release. Below is the new updated icon with a more 3D aspect, and more detail in the firefox’s snout, ears, and hands.


Privacy is a main topic in this release: a new Private Mode (accessible from the Tools menu) has been introduced that lets a user browse knowing that all his tracks (downloads, history, forms, passwords, cookies, etc.) will be cleared as soon as he returns to normal mode or exists Firefox.

Start private mode

It can also be set to be the default mode through the revamped Privacy preferences page in the Options window.


Another big aid for privacy is an option to delete all traces of a web site through the Library or the History sidebar by right-clicking on a web page and clicking on Forget About this Site.

If you prefer to delete tracks based on time (like for the last 4 hours), the Clear private Data option in the Tools menu has been replaced with Clear Recent History, which lets you select what to delete and for what period of time (1, 2, 4 hours, the day or everything).


Users previously concerned with the awesome bar providing too much information through its autocomplete menu, can now disable History and/or Bookmarks suggestions from appearing.

Tabbed browsing gains a new tab button (without losing the classic you can put anywhere in your toolbar), options to drag tabs out of the window to their own, getting them back, true tab cloning. The tab bar is now visible by default making the throbber unnecessary as it is already present in each tab. Plus, you can now restore a recently closed window with all its tabs unlike previous versions.

Performance-wise, this release is significantly faster that Firefox 3 running web applications, thanks to the introduction of TraceMonkey, a technology that allows just in time JavaScript compilation for faster execution. Despite these improvements however, Chrome currently holds the crown for speed with better results in the main JavaScript performance tests, thanks in part to its V8 JavaScript engine.

Places, the history+bookmarks database is now significantly faster due to several improvement to the querying. Web feeds refresh has also been optimized so it won’t hang Firefox if updating several feeds at the same time.

But despite all the good , significant improvements Firefox 3.5 has stacked in the last year of development, it’s its web development oriented enhancements which will make this release most memorable: support for geolocation enabled sites, which means Firefox is now able to tell a site where you are if you agree to do so, for a more customized experience; support for @font-face, a CSS feature that allows embedding of fonts in web pages so visitors get the content as intended; media queries, a blurry name for a cool feature that will allow sites deliver content based on the specific device characteristics such as aspect ratio, resolution, color capabilities, and more; cool 3D and image/font effects thanks to the <canvas> element; and lots of others.

Among these, the most significant is the added support for <audio> and <video> tags, plus the bundle of a Theora/Vorbis (video and audio) decoders, so developers can now create audio and video content for free in these great performing, open source, royalty free codecs that will enable better web video applications as the Flash plugin barrier has a viable option.

This new video option is starting to attract attention, with YouTube making some tests with it, and Dailymotion already announcing the support for the HTML5 video tag and the codec.

Mozilla is running a series of cool examples of what can be done with the new capabilities that Firefox 3.5 will feature at It’s definitely worth a look.

For Mozilla, a release candidate means “what will be shipped unless a major bug is discovered”, so if you download RC2 you may as well be using the final version as it would just be renamed.

Firefox 3.5 final is expected by the end of June. The Firefox team is now focused on the next major update, tentatively named 3.6, but more safely called by its code name: Namoroka.

Get Firefox 3.5 RC 2 available for Windows, Mac OS X and Linux in over 70 languages.

5 thoughts on “First look to Firefox 3.5 RC2”

  1. Firefox needs the put the tabs bar in the blue bar at the top of the windows like chrome does, so that the pages are displayed in a bigger area.
    Please report this to the mozilla team!!

  2. Please tell firefox developers to move the tabs to the top bar son you can have a bigger area for browsing. Similar to chrome

  3. Firefox needs a function to disable tabbed browsing in their 3.5 version. I don’t find tabbed browsing very useful or time saving.

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