Are you refering to what happens when creating "Multi-Body" models? [default nameing..."Design Body_1"]
AHA....that happens only after creating the "Flat Pattern"....as in the "Design" state [or the "Flat Pattern" state] for display & creating draft views.
That happens as soon as you create a flat pattern of a sheet metal part to designate the Design model part of Pathfnder as opposed to the Flat Pattern model part of Pathfinder.
Yea, I posted that and after it update I saw you beat me by 4 seconds!