What's happening is that with this code:

**HTML**

```
<div class="one">

    <div class="will-overflow">
    </div>
</div>

```

**CSS**

```
html, body {
    width: 100%;
    height: 100%;
}

.one {
    height: 100%;
    background: red;
}

.one .will-overflow {
    width: 20%;
    height: 2000px;
    background: blue;
}

```

I get a result like this:
![enter image description here](https://i.stack.imgur.com/xExwd.png)

**Demo**

<http://jsfiddle.net/kM46e/>

**Question**

Is there anyway to expand the div.one height to fit the **div.will-overflow**. This is just an example, the content of that div is dynamic.