Firefox 1.5 Beta 1 has been released and features a number of new features and a lengthy list of big and performance fixes. This is beta software though - the Firefox welcome screen you see after you install the software reminds you of this and the download page cautions you to think about whether you want to use test phase software or the current official release.

Here's a list of the major new features:

• Automated update to streamline product upgrades. Notification of an update is more prominent, and updates to Firefox may now be half a megabyte or smaller. Updating extensions has also improved.

• Faster browser navigation with improvements to back and forward button performance.

• Drag and drop reordering for browser tabs.

• Improvements to popup blocking.

• Clear Private Data feature provides an easy way to quickly remove personal data through a menu item or keyboard shortcut.

• Answers.com is added to the search engine list.

• Improvements to product usability including descriptive error pages, redesigned options menu, RSS discovery, and "Safe Mode" experience.

• Better accessibility support including DHTML accessibility.

• Report a broken Web site wizard to report Web sites that are not working in Firefox.

• Better support for Mac OS X (10.2 and greater) including profile migration from Safari and Mac Internet Explorer.

• New support for Web Standards including SVG, CSS 2 and CSS 3, and JavaScript 1.6.

• Many security enhancements.

• List of notable bug fixes since Deer Park Alpha 2

Let me say right now that the improvements to Extension updating are immediately visible. The application checked my existing installation of extensions and found that all but one were incompatible with this new version. The compatible one required an update, which the extension compatibility checker fetched and installed for me. Very nice.

Performance feels improved after a short period of use. I'll update this post later today after I see if either of my two big issues with Firefox 1.0.5 have been resolved - a memory leak issue when Firefox has been running for a few hours and an unfortunate tendency to leave firefox.exe processes running after I visibly exit the browser.

UPDATE: Neither of these issues seems to be fixed yet. Some odd JavaScript issues I've encountered in the previous two official releases have been corrected. I've uninstalled the beta and gone back to version 1.0.6 for now. The new enhancements are simply not compelling enough to deal with the loss of all of my extensions. I'll revisit the new version once some of these extensions have been updated but running barebones Firefox is not something I'm willing to go back to.