I am not at my computer to try this atm, so going from memory... But If I remember correctly, if you click the clip you want, then press and hold ctrl on your keyboard then drag the clip to a new track, it creates a duplicate of that clip? You can also click the clip, press and hold ctrl + shift and this will duplicate the clip and align it exactly where it is in the track you are copying it from.
Give that a try?
P.S. if ctrl doesn't work, try alt?