L3xu5 Mum

Having taken delivery of a pre-used 2010 rx450h I am having fun & games getting to grips with her! Forgive me if this is a daft question (I am sure I will ask more!) but is it usual for the car to roll back when on a small incline? Yesterday I was waiting to give way to oncoming traffic and whilst the gearbox was in Drive she started slowly rolling back down the hill and didn't stop until I applied the brakes! My old Merc which I chopped in to get the Lexus didn't...