code: function() {
          var canApply = true;
          for (var i=0, len=this.layers.length; i<len; i++) {
              if(!this.wfsCache[this.layers[i].id]) {
                  canApply = false;
                  break;
              }
          }
          canApply && this._queue.call(this);
      }
docs: Method: applySelection
  Checks if all required wfs data is cached, and applies the selection