code: protected void updateTrackLocation( SetTrackInfo<Desc> info, FastQueue<AssociatedIndex> matches) {
  		info.matches.resize(matches.size);
  		for (int i = 0; i < matches.size; i++) {
  			info.matches.get(i).set(matches.get(i));
  		}
  
  		tracksActive.clear();
  		for( int i = 0; i < info.matches.size; i++ ) {
  			AssociatedIndex indexes = info.matches.data[i];
  			PointTrack track = info.tracks.get(indexes.src);
  			Point2D_F64 loc = info.locDst.data[indexes.dst];
  			track.set(loc.x, loc.y);
  			tracksActive.add(track);
  		}
  	}
docs: Update each track's location only and not its description.  Update the active list too