@VectorStyler
EDIT: Ah, I understand now: you meant the functions under Edit-->Attributes. I didn't know of these yet I think the procedure is still cumbersome in comparison as stated below. Also I get an unintended offset.
I dont know if I understand you, but if I replicate your suggestion stepwise it does not produce a new path on top of a mask and the masked elements.
Sorry for referring til AI; it's makes it perhaps a bit unclear:
AI: When I select a shape (the mask)with select tool (A), change tol select tool (V) and thus paste in front (cmd-F) I'll achieve what I want: a duplicate on top. This also goes for grouped shapes/objects and is useful for fast editing of effects exactly on top of an existing visual element.