Filming and Editing

We started filming for the video about a month ago and the shots we have got have been really successful. so far we filmed scenes of "Katy" running away, sitting in fast food restaurants, throwing money, drinking and singing into the camera whilst wearing various different outfits like a wedding dress, bright quirky clothing. so far all filming has gone well and we have even started to edit the clips by matching them up to the song, the editing began well but recently has become very difficult as we can't seem to lock clips down so they stop moving along the time line when another clip is added.