Parainvite and google behaviour

Hi, we done the google setup, but we are really surprised to see how it works.

Everythings it is ok, but the retrieved list of users to invite is the set of our Gmail contats list elements that are in our social (cucina.it) and not yet our friends.
We always supposed that this components was intended to invite friends from i.e. google not yet in cucina.it (not our friends). We supposed to be able to select from the entire list of our Gmail contats items (like FB of parainvite done).
It is the normal behaviour?
Cheers
Massimo