Thunderbird 3 beta 3 is now available to download for Winows, Mac and Linux users. The beta introduces some significant improvements to the open-source desktop client, from performance to interface.
The new beta is built on Mozilla's Gecko 1.9.1.1 platform, keeping it up to date with the latest changes that affect Firefox. Mozilla also claims that there are more than 500 changes in this version, and hints at more alterations to come by stating in a press release .
he interface and behavioral changes in this beta are significant and should be easy to spot for longtime 'bird-watchers. The biggest is that Thunderbird now supports e-mail tabs. If you've checked out the highly unstable Shredder version of Thunderbird, or Postbox, a competitor that's based on Thunderbird's own open-source code, you've known that this feature has been due for a while.
Hitting Enter or double-clicking a message will now open it in a new tab and make it your focus. Middle-click an e-mail to open it in a new tab but retain your focus on the current tab--usually the folder pane. You can switch tabs via the hot key combo CTRL+Tab, and the new tab menu button on the right side of the tab bar will help you manage your tabs.
Another new feature is the message summary view, which you can see when you select multiple messages at once. They'll open in the message preview pane. Changes to folders include a Smart Folders mode, which gives users the ability to combine inboxes from multiple accounts, and the new ability to customize column headings on a per-folder basis.
Thunderbird 3 beta 3 for half a day, users with large inboxes should be careful to note that Thunderbird now adds all your messages to its search archives. This can hamper performance until it's completed. Also note that the calendar extension Lightning isn't compatible with beta 3 unless you're using the nightly build.