code: function(point,tipGroup){
      var _self = this,
        sArray = [],
        //prePoint = _self.get('prePoint'),
        tipInfo;
  
      if(!tipGroup.get('shared')){
        var activedItem = _self.getActived();
        activedItem && sArray.push(activedItem);
      }else{
        sArray = _self.getSeries();
      }
      Util.each(sArray,function(series){
        if(series && series.get('stickyTracking') && series.get('visible')){
          series.onStickyTracking({point : point});
        }
      });
      if(sArray.length){
        tipInfo = _self._getTipInfo(sArray,point);
        if(tipInfo.items.length){
          _self._showTooltip(tipInfo.title,tipInfo.point,tipInfo.items);
        }
      }
    }
docs: 处理鼠标跟随事件