Firefox 4.0, the next major release of Mozilla’s open source browser, will bring to the table a major overhaul of its graphical user interface, one that would put the UI in line the Windows 7 Ribbon/Fluent style.

Mozilla has already made public details on the revamping of the Firefox User interface for version 4.0, and various concepts and sketches have been already published. However, Firefox 4.0 developer Stephen Horlander has now offered two video demonstrations featuring Firefox 4.0’s new GUI available here and here. For the best viewing experience possible users should run Firefox 3.6 (download links available at the bottom of this article).

“In addition to the UI and appearance changes we have been exploring for Firefox, we have also been exploring how to better improve the user experience through animation,” Horlander stated. “One area that animation would be very beneficial is with tab interactions. Specifically moving/arranging tabs on the tab strip, closing/opening tabs and tearing off tabs into new windows. Presently the feedback here isn’t as good or as elegant as it could be.”

Both videos are extremely short and users will have to watch carefully in order to witness the advances in terms of animation and tab functionality that Mozilla is cooking for Firefox 4.0. In the first video, Horlander clicks on the New Tab button. Subsequently, it is the tab button itself that grows and “gives birth” to the new tab. The second video offered is designed to illustrate the changes introduced to standard Firefox tab behavior such as rearranging tabs. At the same time, users will be able to watch how Firefox 4.0 will react when a tab is torn-off.

“Some of the goals for animation are to make browsing feel faster, adding visual affordances that makes tasks more understandable and to make the browser more visually appealing. There is much more detail on the Wiki articles linked above. My goal was to quickly demo how this would actually look and feel because still images and wireframes can only convey so much,” Horlander added.

Most importantly, the videos both feature the new Firefox 4.0 GUI, which just as the Windows 7 Ribbon/Fluent user interface, no longer features the classical menu. Instead, Firefox 4.0 will offer the App Button which will open the way to the Menu items. As you can see, Firefox 4.0 will also feature a reduced Title Bar, and re-arranged tabs, to a new position, above the address