I believe it still had applications in the UI and it was architected with persistent but more-or-less trad objects, so not what I call "Inverted". Your stuff, like contacts, messages, notes and events, could only be interacted with within the boundaries of their apps rather than being free-floating and having "physical" properties, like weight, being stackable and pinnable etc. There wasn't anything in the UI to allow arbitrary mashing up of the stuff on the desktop there, like grabbing a contact from the Rolodex (!) and stapling it to the diary on tomorrow's date page.