In Diablo, the single hildon-desktop process implemented the Home for desktop applets, Statusbar for the status applets on top of the screen, Task Navigator for launching and switching between applications, Dbus service for notifications and compositing functionality for transparency in applets.

Programming errors in these different types of applets often caused hildon-desktop process to crash and restart. After a restart following such a crash, hildon-desktop would only load a 'safe' set of applets, excluding applets that were not part of the sales package.

In Fremantle, the widgets (formerly known as applets) are removed from the process implementing window management, application switching, application launching and drawing of the Home. This separation will allow for better reliability in aforementioned functions...

...a novel, transparent widget based interface. Each running application gets it’s own semi-transparent widget to put it’s content in. Multiple applications can be stored in memory “for months”. E.g. when you are writing a document or e-mail, just swipe the finger through the screen and semi-transparent panels with active or pre-set applications and their content pop-up. Select one and you can start working with it at once.

well so far the screenshots looks like canola gone desktop...

thats why i would like to check it out first hand...