

Mozilla has announced the availability of the fourth Firefox 4 beta release. The new beta brings some extremely significant new features that have been gestating in Mozilla's labs, including built-in synchronization functionality and a sophisticated new tab management system.

Tabs have arguably had a major impact on how users operate Web browsers, but the concept hasn't scaled very well as browsing habits become more complex. Mozilla devised a compelling solution with its Tab Candy concept, which allows users to arrange groups of tags in spatially-organized collections. Mozilla's experimental implementation of Tab Candy has matured swiftly and is going to be fully integrated in Firefox 4. It's available for testing in the new beta release, though it's said to not be fully feature-complete yet.



[arsimg src="https://cdn.arstechnica.net/wp-content/uploads/archive/ff4b4/screenshot1.png"]Firefox Panorama[/arsimg]

The tab groups in the Panorama show thumbnails and titles of the individual tabs. You can create a new group container by clicking and dragging in a diagonal motion in the empty space between the groups. You can also close multiple tabs at once by closing a group. In regular browsing mode, the tabs in the tab bar have a new right-click context menu item that lets you move a tab to a different group without having to activate the Panorama.

Although the Firefox Panorama is a lot more functional today than the feature was in the original experimental builds, it still suffers from some limitations. The browser's existing "bookmark all tabs" feature will bookmark only the tabs in the current group. Although that is not an unreasonable behavior, it would be nice if there was also a way to still bookmark all open tabs in a window. In general, there needs to be a simpler and more transparent way to move groups in and out of the bookmark system.

Each individual window has its own set of groups and there is no way to drag a whole group from one window to another. It would be nice if there was a way to zoom the panorama out another level so that you could see all of your groups from all of your windows. Another problem is that there is no way to select multiple tabs at once. It would be useful to be able to lasso a small cluster of tabs from one group so that you could move those individual tabs to another group at the same time. Similarly, it would be useful if there was a way to merge groups.

### Synchronization

Mozilla began to develop a synchronization framework called Weave several years ago, with the aim of providing a way for users to keep their bookmarks and history consistent between multiple computers. Mozilla offers its own hosted service for storing the data, with encryption all the way across so that the user's privacy is preserved.

Weave has been offered for quite some time as a Firefox add-on, but now the functionality is finally ready to be integrated directly into the browser. Firefox synchronization is included out of the box in beta 4. The user simply has to click the synchronization icon in the bottom right-hand corner of the window or select the relevant item from the Tools menu. When the user tries to enable synchronization for the first time, they will be prompted to configure a Firefox Sync account. The configuration wizard will explain how the feature works and will walk the user through the simple setup process.

After it is configured, synchronization will be performed automatically, in a manner that is unobtrusive and entirely transparent to the user. Synchronization settings can be configured from the new Sync tab of the standard Firefox preference dialog. You can even see the tabs that you have open on other computers by by selecting the associated option from the Tabs menu. Sadly, this feature isn't smart enough to understand tab groups yet.

The Firefox Sync features also work with Fennec, Firefox's mobile browser for Android and Maemo. It also works with the Firefox Home application for Apple's iPhone, which recently launched in the App Store.

One of the greatest things about Firefox Sync is that it uses an open protocol that is conducive to third-party implementations. This means that developers will be able to create their own client and server software that can interoperate with Firefox's synchronization features. This is especially useful for users who want to be able to self-host their own server-side synchronization infrastructure. For a really great example, you can check out this implementation by Mozilla's Les Orchard that allows you to run your own Sync server on App Engine.

### Conclusion

Firefox 4 is shaping up to be very impressive and offers an excellent feature set. Mozilla is also still aggressively working on performance improvements and user interface refinement to make sure that Firefox 4 is competitive on all fronts.

[arsimg src="https://cdn.arstechnica.net/wp-content/uploads/archive/ff4b4/browser.png"]Firefox 4 beta 4 on Windows[/arsimg] [arsimg src="https://cdn.arstechnica.net/wp-content/uploads/archive/ff4b4/screenshot2.png"]Firefox 4 beta 4 on Linux[/arsimg]

Competition in the browser market has increased substantially over the past few years, leading to some unexpected changes in the marketplace. Firefox has fallen far behind in several key areas, including JavaScript performance and multiprocess browsing. Mozilla has a reasonable roadmap for getting back to the front of the pack, but the organization has to contend with the limitations of a browser codebase that has a lot of legacy cruft.

Despite its historical weaknesses, Mozilla's Gecko rendering engine still has a lot of relevance and offers many unique strengths. Mozilla's engineering capabilities are significant and the organization has delivered seemingly miraculous improvements to Firefox in the past. When Firefox 3 launched in 2008, its memory footprint was smaller than any other mainstream browser at the time—a feat that few would have imagined possible for a browser that was often derided for perceived bloat.

Mozilla can still bring Firefox back into the lead. The feature set for Firefox 4 is strong, now Mozilla needs to match the superior performance, responsiveness, and robustness of rivals like Chrome and Opera.

