Mozilla nudged Firefox 3.6.4 one step closer to its official release by pushing out the first release candidate version of the browser. Meanwhile, Weave Sync has been re-branded Firefox Sync in anticipation of its eventual inclusion in the Mozilla product. Available for Windows, Mac, and Linux, Firefox 3.6.4 Release Candidate 1 began rolling out to Firefox beta users on May 28th and is notable for locking down the features and fixes the browser maker has been working on since January. For its part, add-on Firefox Sync 1.3 introduces a menu option under History for automatically pulling up the about:sync-tabs list of tabs synchronized from other computers. It also adds further refinements to the setup process, alongside its name change.

Firefox 3.6.4 will incorporate out-of-process plug-in protections. (Credit: Mozilla)

Assuming no major bugs are discovered, Mozilla is expected to quickly graduate Firefox 3.6.4 as the final version of the browser because of the new Out-of-Process Plug-in (OOPP) "sandboxing" feature. OOPP prevents plug-in crashes from Adobe Systems' Flash, Apple's QuickTime, and Microsoft's Silverlight from bringing down the entire browser. Mozilla's calendar says that this version of the browser, code-named "Lorentz," should be ready at the beginning of June.

Other browsers, such as Google's Chrome, also offer sandboxing. Mozilla's version, which the publisher touts as allowing users to experience "uninterrupted browsing," is slightly different in that it relates only to the specific aforementioned plug-ins, and that when one of them crashes, only the plug-in component of the page becomes unusable. A page crash in Chrome leads to a replacement of the entire page with an icon indicating that a crash has occurred. Non-OOPP crashes in Firefox will still take down the whole browser.

Firefox Sync marks a level of maturation in the synchronization project that indicates Mozilla's confidence in the add-on. In a blog post, Mozilla stated that it will be working toward incorporating Sync as a standard feature in Firefox. While not common for Mozilla, this isn't unusual since the theme-switching Personas started off in Mozilla Labs as an add-on, and is now a core feature of the browser.

Sync can be found under the Tools menu or on the Status bar at the bottom of the browser. It currently allows users to synchronize bookmarks, preferences, passwords, history, and tabs. The new option to easily access synced tabs has been added as Tabs from Other Computers under History. Users can also toggle synchronizing an account without having to re-enter their username or password using the Disconnect button next to their account name in the Sync tab on the Option menu. Firefox Sync replaces features that have been previously available only from third-party add-ons such as Xmarks.

Firefox Sync now has a button under the History menu to easily pull up the list of synced tabs from other computers. (Credit: Screenshot by Seth Rosenblatt/CNET)

Firefox Sync's setup has seen refinements in nearly every iteration of the add-on. It's currently not overly complicated, but for users who want clear instructions Mozilla has created a step-by-step guide through the most recent setup changes.

The technology used in Sync has also led toward mobile development. The new Firefox Home app for the iPhone will let iPhone OS users access their Firefox history, bookmarks, and open tabs without actually browsing in Firefox.

Firefox Sync started a bit rough, with frequent user complaints about stability and effectiveness. While those haven't died off completely, it's clear that if you had a bad experience with the plug-in earlier, it's worth giving it another look now.