– Fixed a single stability issue affecting a limited number of users
– Fixed a stability issue affecting Windows users.
– Fixed an issue causing rendering errors with plugins affecting Mac OS X users.
– See the complete changelist from the previous beta.
As well as these features from previous Firefox 4 Betas:
– Firefox 4 Beta is available in 39 languages.
– Support for the new proposed Audio Data API
– Direct2D Hardware Acceleration is now on by default for Windows 7 users
– Firefox button has a new look for Windows Vista and Windows 7 users
– Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL.
– Firefox Sync is now included by default.
– A new feature gives users a visual overview of all open tabs, allowing them to be sorted and grouped.
– Firefox now supports the HTML5 video „buffered“ property.
– Tabs are now on top by default on Windows and OSX – Linux will be changing when the theme has been modified to support the change.
– You can turn any tab into an „App Tab“ by right-clicking on it and selecting „Make into App Tab“ from the context menu.
– Web developers can animate content using CSS Transitions.
– Responsiveness and scrolling improvements from the new retained layers layout system.
– Changes to how XPCOM components are registered in order to help startup time and process separation.
– You can search for and switch to already open tabs in the Smart Location Bar.
– New Addons Manager and extension management API (UI will be changed before final release).
– Significant API improvements are available for JS-ctypes, a foreign function interface for extensions.
– The stop and reload buttons have been merged into a single button on Windows, Mac and Linux.
– The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you’d like).
– Crash protection for Windows, Linux, and Mac when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins.
– CSS Transitions are partially supported.
– Full WebGL support is included but disabled by default at this time.
– Core Animation rendering model for plugins on Mac OS X. Plugins which also support this rendering model can now draw faster and more efficiently.
– Native support for the HD HTML5 WebM video format.
– An experimental Direct2D rendering backend is available on Windows, turned off by default.
– Web developers can use Websockets for a low complexity, low latency, bidirectional communications API.
– Web developers can update the URL field without reloading the page using HTML History APIs.
– More responsive page rendering using lazy frame construction.
– Link history lookup is done asynchronously to provide better responsiveness during pageload.
– CSS :visited selectors have been changed to block websites from being able to check a user’s browsing history.
– New HTML5 parser.
– Support for more HTML5 form controls.
– Web authors can now get touch events from Firefox users on Windows 7 machines.