cover-view自定义页面头部导航，页面卡顿.复现流程：跳转二级页面后台挂起10分钟，在进入当前页面，页面出现滑动和点击卡顿5~10秒的bug

以下为头部自定义导航代码：

<cover-view class="nav-bar {{type}}" style="height: {{navHeight}}px; opacity:{{type != 'transparent' ? 1 : opacity}}">

  <cover-view

    style="padding-top: {{ navTop }}px; text-align: center; width: 100%; ">

    <cover-view style="display:inline-block; height: {{ menuButtonHeight }}px;line-height: {{ menuButtonHeight }}px; " bindtap="dropdown">

      {{title}}

      <cover-view class="dropdown" wx:if="{{dropdown}}">

        <cover-image wx:if="{{ arrow == 'up' }}" src="https://hmpcloud-static.oss-cn-shenzhen.aliyuncs.com/app/images/icon_up.png" />

        <cover-image wx:if="{{ arrow == 'down' }}" src="https://hmpcloud-static.oss-cn-shenzhen.aliyuncs.com/app/images/icon_down.png" />

      </cover-view>

    </cover-view>

  </cover-view>

</cover-view>

<cover-view bindtap="back" class="nav-bar-icon-box" style="top: {{navTop - 15 + menuButtonHeight/2}}px;">

  <cover-view wx:if="{{ back }}" style="opacity:{{type != 'transparent' ? 1 : opacity}}" class="nav-bar-icon {{type}}">

    <cover-image wx:if="{{ arrowColor == 'black' }}" src="../../../images/icon_return.png" style="opacity:{{type != 'transparent' ? 1 : opacity}}" class="img_black {{type}}"/>

    <cover-image wx:else src="https://hmpcloud-static.oss-cn-shenzhen.aliyuncs.com/app/images/icon_back.png" style="opacity:{{type != 'transparent' ? 1 : opacity}}" class="nav-bar-icon {{type}}"/>

  </cover-view>

  <cover-image wx:if="{{ home }}" src="https://hmpcloud-static.oss-cn-shenzhen.aliyuncs.com/app/images/icon_home.png" style="opacity:{{type != 'transparent' ? 1 : opacity}}" class="nav-bar-icon {{type}}"/>

</cover-view>

<cover-view wx:if="{{type != 'transparent'}}" class="nav-bar-placeholder" style="height: {{navHeight}}px;">

</cover-view>