code: function(event){
      if (this.mouseDownMoveHandler) return;
      var pos = this.getEventPosition(event);
      E.fire(this.el, 'flotr:mousemove', [event, pos, this]);
      this.lastMousePos = pos;
    }
docs: Observes mouse movement over the graph area. Fires the 'flotr:mousemove' event.
  @param {Event} event - 'mousemove' Event object.