From the "Modern Web Browser' files:

Mozilla is out now with Firefox 4 Beta 12 and it fixes a very, very, very long list of bugs.

By my count it fixes at least 659 identified bugs (count 'em yourself if you want..).

The improvements are also non-trivial and deal with stability and performance across the board. There are dozens and dozens of crash fixes for all kinds of things and fixes for really odd flaws too.

Among the *odd* flaws that are now fix are:



626940 Zoom out transition doesn't show if repeats zooming in and out of the same item 635142 <strong> not showing bold text

This Beta also takes very specific aim at improving Flash player and other add-ins stability and performance within Firefox 4.

For me thought there is one fix that stands out about the 658 others and it's one for a memory leak issue which, I know lots and lots of people have complained about, Bugzilla entry 630932, "High memory usage by the JS Engine even with no tabs open for > 12 hours "