code: function (evt) {
          this.mouseDown = false;
          this.stoppedDown = this.stopDown;
  
          // check keyboard modifiers
          if(!this.checkModifiers(evt)) {
              return true;
          }
          // ignore double-clicks
          if (this.lastUp && this.lastUp.equals(evt.xy)) {
              return true;
          }
          if (this.lastDown && this.passesTolerance(this.lastDown, evt.xy,
                                                    this.pixelTolerance)) {
              if (this.touch) {
                  this.modifyFeature(evt.xy);
              }
              if(this.persist) {
                  this.destroyPersistedFeature();
              }
              this.lastUp = evt.xy;
              this.finalize();
              return !this.stopUp;
          } else {
              return true;
          }
      }
docs: Method: up
  Handle mouseup and touchend.  Send the latest point in the geometry to the control.
  Return determines whether to propagate the event on the map.
  
  Parameters:
  evt - {Event} The browser event
  
  Returns:
  {Boolean} Allow event propagation