firefoxoverflow-y不能使用嵌套的flexbox

我设计了一个100%宽度100%高度布局与css3 flexbox,它适用于IE11(如果IE11仿真正确,可能在IE10上).

但Firefox(35.0.1),overflow-y无效.正如你在这个codepen中看到的那样:http://codepen.io/anon/pen/NPYVga

firefox没有正确渲染溢出.它显示了一个滚动条

html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
  border: 0;
}
.level-0-container {
  height: 100%;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -webkit-flex-direction: column;
  -ms-flex-direction: column;
  flex-direction: column; 
}
.level-0-row1 {
  border: 1px solid black;
  box-sizing: border-box;
}
.level-0-row2 {
  -webkit-box-flex: 1;
  -webkit-flex: 1;
  -ms-flex: 1;
  flex: 1;
  border: 1px solid black;
  box-sizing: border-box;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: horizontal;
  -webkit-box-direction: normal;
  -webkit-flex-direction: row;
  -ms-flex-direction: row;
  flex-direction: row;
}
.level-1-col1 {
  width: 20em;
  overflow-y: auto;
}
.level-1-col2 {
  -webkit-box-flex: 1;
  -webkit-flex: 1;
  -ms-flex: 1;
  flex: 1;
  border: 4px solid blue;
  box-sizing: border-box;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -webkit-flex-direction: column;
  -ms-flex-direction: column;
  flex-direction: column;
}
.level-2-row2 {
  -webkit-box-flex: 1;
  -webkit-flex: 1;
  -ms-flex: 1;
  flex: 1;
  border: 4px solid red;
  box-sizing: border-box;
  overflow-y: auto;
}

    


        

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