anchor.diff:    var layer = new wax.g.connector( tilejson );
     var layerID =  this.overlayMapTypes.push( layer );
     if( options.disabled ) {
  -    this.overlayMapTypes.setAt( layerID - 1, null);
  +    this.overlayMapTypes.setAt( layerID - 1, emptyLayer);
     }
     // add a utfgrid data layer and custom JS events to catch interactivity
     if( options.interactivity ) {
  
positive.code:     document.selection.empty();
    }
  };
  
  // extend parts of the Google Marker class
  google.maps.Marker.prototype.observation_id = null;
  
negative.code:     .on({
        on: function(o) {
          // check to see if the layer with the interaction is enabled
          if( map.overlayMapTypes.getAt( layerID - 1 ) === emptyLayer ) {
            return null;
          }
          interactionOn = true;
  