content vertical, context horizontal. Not so revolutionary.
Arbitrary scroll left and right with arbitrary window widths is going to be tiresome, and good luck keeping up with what the window manager in that demo is doing when you're tired.
Scrolling automatically to the window that has focus? Narp. Applications that are half off the screen? Why? It's just extra cognitive load.
It's not good.
Accessibility is an issue though. If i could three finger scroll context horizontally that would be nice.