If you change the desktop model you change the desktop. What is shown in one model may not be shown in another. I Like the folder view myself but I generally don't point it to my desktop folder I point my main to ~/ and I have 3 other desktops defined one points at my HTML development folder another to Dektop and another to my program development folder. So I can change to another Desktop and I am set up for a new activity.

You can do the same thing with activities or mix both ways together ie multiple Desktops with multiple activities