使用mui.min.js区域滚动的时候报错，但使用mui.js未报错，希望mui的开发人员能看一下。

详细问题描述
使用mui.min.js区域滚动的时候报错，但使用mui.js未报错。

重现步骤
使用mui.min.js时。
代码片段：

<div class="mui-content  mui-scroll-wrapper">  
            <div class="mui-scroll">  
                区域滚动中要放置的内容区域  
            </div>  
        </div>

[结果]
mui.min.js:1958 Uncaught DOMException: Failed to execute 'querySelectorAll' on 'Element': '.mui - scroll' is not a valid selector.
at d._reInit (http://127.0.0.1:8020/BoChengWap/js/mui.min.js:1958:31)
at d.refresh (http://127.0.0.1:8020/BoChengWap/js/mui.min.js:1966:11)
at d.init (http://127.0.0.1:8020/BoChengWap/js/mui.min.js:1683:150)
at new d (http://127.0.0.1:8020/BoChengWap/js/mui.min.js:1521:34)
at HTMLDivElement.<anonymous> (http://127.0.0.1:8020/BoChengWap/js/mui.min.js:2032:27)
at http://127.0.0.1:8020/BoChengWap/js/mui.min.js:149:14
at Array.every (<anonymous>)
at Array.each (http://127.0.0.1:8020/BoChengWap/js/mui.min.js:148:20)
at Array.a.fn.scroll (http://127.0.0.1:8020/BoChengWap/js/mui.min.js:2019:16)
at http://127.0.0.1:8020/BoChengWap/html/index.html?__hbt=1506760521521:50:31```javascript

[期望]  

运行环境  
[mui版本]  * Mui v3.7.0 (http://dev.dcloud.net.cn/mui)  

附件  
[代码片段]  
<div class="mui-content  mui-scroll-wrapper">  
            <div class="mui-scroll">  
                区域滚动中要放置的内容区域  
            </div>  
</div>