el-popover 有多个可滚动的父容器时，内容只跟随最近的父容器滚动，较远的父容器滚动时el-popover内容不跟随滚动（解决办法）

版本依赖(参考)

1. vue 2.7.x
2. element-ui 2.15.x

   <el-popover ref="popover" placement="bottom-start" width="286" trigger="click" >
    <el-button icon="el-icon-plus" slot="reference" type="primary"></el-button>
  </el-popover>

export default{

  mounted() {
      window.addEventListener('scroll', this.handleScroll, true)
  },
  destroyed(){
      window.removeEventListener('scroll',this.handleScroll,true)
  },
  methods: {
    handleScroll() {
      if(!this.$refs.popover){
        return
      }
      this.$refs.popover.updatePopper()
    },
  }

}