code: function() {
          if (this.map) {
              this.map.events.un({
                  "removelayer": this.handleMapEvents,
                  "changelayer": this.handleMapEvents,
                  scope: this
              });
          }
          this.layer = null;
          OpenLayers.Control.prototype.destroy.apply(this, []);
      }
docs: APIMethod: destroy
  Take care of things that are not handled in superclass.