Well my side molding was doing the same thing and on mine there is a track that it sets in. Now whether its the clips mentioned above or not Im not sure, it looked to be a long track to me. But I was able to lift up on the molding and simultaneously push back on it and reseat it in the track. I havent had any trouble with it since.
So if you feel courageous you may lay down on the ground and pull back on that molding and see what you see up in there and if there is a track then do what I did. Otherwise you'll have to take the advice offer by those above.
