anchor.diff:      .on({
         on: function(o) {
           // check to see if the layer with the interaction is enabled
  -        if( map.overlayMapTypes.getAt( layerID - 1 ) === null ) {
  +        if( map.overlayMapTypes.getAt( layerID - 1 ) === emptyLayer ) {
             return null;
           }
           interactionOn = true;
  
positive.code:     // we need to secure the layerID so that we can add the layer in the proper
      // places when the user selects it. That is why the layer is added
      // above and immediately set to null here.
      this.overlayMapTypes.setAt( layerID - 1, null);
    }
    if( this._overlayControl ) {
      this._overlayControl.addWindshaftOverlayControl(
  
negative.code:   var layer = new wax.g.connector( tilejson );
    var layerID =  this.overlayMapTypes.push( layer );
    if( options.disabled ) {
      this.overlayMapTypes.setAt( layerID - 1, emptyLayer);
    }
    // add a utfgrid data layer and custom JS events to catch interactivity
    if( options.interactivity ) {
  