element UI Cascader控件在IE11在filterable 状态下 CascaderPanel 初始化问题

在IE11下 CascaderPanel 初始化总是显示，添加了先禁用 filterable 再获取焦点后改变 filterable

 <template>
  <div id="app">
    <el-cascader
    :options="options"
    :props="props"
    :collapse-tags="collapsetags"
    :filterable="collapsetags"
    @blur="fun1"

    ></el-cascader>

  </div>
</template>

<script>
export default {
  name: 'App',
  methods: {
    fun1 () {
      this.collapsetags = true
    }
  },
  data () {
    return {
      collapsetags: false,
      items: {},
      props: { multiple: true },
      options: [{
        value: 1,
        label: '东南',
        children: [{
          value: 2,
          label: '上海',
          children: [
            { value: 3, label: '普陀' },
            { value: 4, label: '黄埔' },
            { value: 5, label: '徐汇' }
          ]
        }, {
          value: 7,
          label: '江苏',
          children: [
            { value: 8, label: '南京' },
            { value: 9, label: '苏州' },
            { value: 10, label: '无锡' }
          ]
        }, {
          value: 12,
          label: '浙江',
          children: [
            { value: 13, label: '杭州' },
            { value: 14, label: '宁波' },
            { value: 15, label: '嘉兴' }
          ]
        }]
      }, {
        value: 17,
        label: '西北',
        children: [{
          value: 18,
          label: '陕西',
          children: [
            { value: 19, label: '西安' },
            { value: 20, label: '延安' }
          ]
        }, {
          value: 21,
          label: '新疆维吾尔族自治区',
          children: [
            { value: 22, label: '乌鲁木齐' },
            { value: 23, label: '克拉玛依' }
          ]
        }]
      }]
    }
  }
  /* mounted () {
    /*this.$nextTick(() => {
      this.items = document.getElementsByClassName('el-cascader__dropdown')
      this.items[0].style.setProperty('display', 'none')
    }) */
  // },
  /* created () {
    this.$nextTick(() => {
      this.items = document.getElementsByClassName('el-cascader__dropdown')
      this.items[0].style.setProperty('display', 'none')
    })
  } */
}
</script>