The new single button menu omits a lot of the standard items that were easily accessible through Firefox 3 menu. Many of the items left out are easy accessible through contextual menus and other areas of the user interface. Features like private browsing and the download window are no longer easily found. You can however bring up the classic menu by hitting 'Alt' to temporarily activate it. Since this is only beta 1, Mozilla will most likely work out these menu details in later versions and the final release.
The new interface is a departure from Mozilla’s old Firefox suite and is one of the most significant appearance overhauls that Mozilla has undertaken.
Plug-ins and Extensions
Firefox 4 beta 1 plug-ins such as Apple QuickTime, Adobe Flash, or Microsoft Silverlight now run in their own separate process which can prevent the entire browser from crashing in the event of an error.
There is also support for WebGL which is an open standard for displaying 3D content in web pages; however it has not been enabled yet in the beta 1 version.
As new Firefox 4 beta releases surface we can expect to see the new Firefox 4 take on a new appearance as well as new features getting added for the final release.
Firefox 4 beta 1 install is available for Windows, Linux, and Mac. Installing Firefox 4 will keep Firefox 3 version intact and usable while letting the user to test out the beta 1 version.
Users who want to try out the new beta release can download it from the Firefox Web site.
Explore further: Software provides a clear overview in long documents
More information: Release Notes, Release Announcements