code: function() {
          var deactivated = OpenLayers.Control.prototype.deactivate.call(this);
          if(deactivated) {
              if(this.source && this.source.events) {
                  this.source.events.un({
                      sketchcomplete: this.onSketchComplete,
                      afterfeaturemodified: this.afterFeatureModified,
                      scope: this
                  });
              }
          }
          return deactivated;
      }
docs: APIMethod: deactivate
  Deactivate the control.  Deactivating the control unregisters listeners
  so feature editing may proceed without engaging the split agent.