Seat Reservations-Air Dolomiti

I don't know specifics about Air Dolomiti, but on all of my intra-European flights (including those that were segments of an international itinerary), the seats were assigned at check-in. Remember, it's a short flight, so unless you have some special situation (like traveling with a child where you don't want to be separated), I wouldn't worry.

In Europe, on intra-European flights, seat assignment is always at check-in. That's the way it goes with almost all European airlines. Exception to this is only for business class passengers or status passengers. So your experience is perfectly normal. This surprises many American passengers, but this is simply the way it works in Europe.