解决VantUI popup 弹窗不弹出或无蒙层的问题

<template>
 <div class="PopupTime">
  <van-popup v-model="popup1show" position="bottom" :overlay="true" @click-overlay="clickOverlay">
   <van-datetime-picker show-toolbar
         :title="popupTitle.popupName"
         v-model="currentDate"
         type="datetime"
         @cancel="onCancel" @confirm="onConfirm" class="font14"/>
  </van-popup>
 </div>
</template>

<script type="text/ecmascript-6">

 export default {
  props:{
   popupTitle:Object,
  },


  data() {
   return {
    popup1show: true,
    currentDate: new Date(),
   };
  },
 methods：{
 clickOverlay() {
 this.onCancel();
 },
 onCancel() {},
 onConfirm(value, index) {},
 }
 </script>

 <popup-time 
 v-show="isShowDelay" 
 :popupTitle="popupDelayT"
 @PopupDelayTime="fromDelayT">
</popup-time>
//import PopupTime组件，并在components中注册

 <popup-time 
 v-if="isShowDelay" 
 :popupTitle="popupDelayT"
 @PopupDelayTime="fromDelayT">
</popup-time>
//import PopupTime组件，并在components中注册

import { Popup } from 'vant';
Vue.use(Popup);
import { Picker } from 'vant'; 
Vue.use(Picker);

<van-popup v-model="show" position="bottom" :overlay="true">
 <van-picker show-toolbar title="请选择区域代理城市" :columns="columns" @cancel="onCancel" @confirm="onConfirm" @change="onChange" />
</van-popup>