Part three in a series of co-posts by Windows 8 Secrets co-authors Rafael Rivera and Paul Thurrott.

Windows 8's worst-kept secret, perhaps, is that it will include a Windows Phone-inspired, Metro-like, tiles-based user interface as an alternative to the more mainstream Aero and Aero Lite (formerly Aero Basic) UIs. Aimed at small, touch-based devices like tablets and phones, this new UI, called Immersive, is also one of Windows 8's most locked-down features. And in the recently leaked builds, it's proven impossible, so far, to unlock.

One clue to the Immersive UI, however, exists in a new Immersive version of Internet Explorer, which looks and works much like Windows Phone's IE Mobile, but uses the desktop IE 9 renderer. Currently, this application--which, oddly enough, is not currently implemented as a Windows Phone-style AppX application package like some other new Windows 8 apps--operates only at 640 x 480, and cannot be resized. It's likely that this application is designed to run full screen only and that the limitations we're currently seeing are because we're running outside of its intended native Immersive environment.

ie_immersive_01_0
IE Immersive.

There isn't much to see yet, though the browser does work. Browser history is implemented similarly to tabs in IE Mobile, with square, simple thumbnails. But IE Immersive picks up some nice site colorization functionality from desktop IE 9 while displaying those tabs in the tabs screen.

ie_immersive_02_0
IE Immersive with History displayed.

--Rafael Rivera and Paul Thurrott