SW07 under XPP, full updates.
Create a part with some holes. Turn the part into an assembly. Add fasteners. Create a folder. Move all the fasteners into the folder.
Now create a new assembly. Insert the above-created assembly. Expand the subtree for the newly inserted assembly. The folder is gone and all the fasteners are listed individually.
If you now open the insterted assembly the folder shows-up again and the fasteners are back inside of it.
As long as the subassembly remains open the folder is visible.
Weird.
-Martin