[Bug Report] Can't remove body's class: el-popup-parent--hidden while using messageBox twice

[VanJunming]

Element UI version

2.3.9

OS/Browsers version

MacOS chrome 66.0.3359.181

Vue version

2.5.13

Reproduction Link

https://jsfiddle.net/mmx38qxw/1962/

Steps to reproduce

1.Using this.$confirm() to alert a messageBox (set the lockScroll as true)
2.User click the confirm/cancel button , receive promise callback
3.Then use another this.$confirm() to alert an other messageBox (set the lockScroll as true)
4.close the last messageBox, the body can't scroll. Find that the body still has a class: el-popup-parent--hidden, it's style is "overflow: hidden"
5.remove the class : el-popup-parent--hidden , the body can scroll.

What is Expected?

need to scroll the body while using the messageBox twice

What is actually happening?

can't scroll

[VanJunming]

I use setTimeout to avoid this bug

[leslieSie]

show me you code

[leslieSie]

@VanFangbo

[VanJunming]

@leslieSie 代码是公司项目的不好透露。看这个吧：https://jsfiddle.net/mmx38qxw/1962/ 。我也是类似于这么使用的。而且这个代码也出了同样的问题