CSS Overflow - Not working as expected

Question

http://jsfiddle.net/bSnaG/

In my mind the above example should look like a grey box with #x not going past the edge and #y poking out the bottom.

But it's not like that - apparently setting overflow-x: hidden; causes overflow-y: scroll | auto;.

Is there any way around this?
I need to allow certain elements to escape the bounding box without setting overflow: visible on #box.

Answer 1

#y can't break out of its bounding box without being taken out of the flow of the document. Does adding position: absolute; to #y give the effect you're after?

Update

Restructured HTML example, including a containing box to allow everything to be easily positioned together. Try it out here: http://jsfiddle.net/GfNbp

<div id="container">
    <div id="box">
        <div id="x"></div>
    </div>
    <div id="y"></div>
</div>


#box {
    width: 100px;
    height: 100px;
    margin: 10px;
    background: #ededed;
    padding: 10px;

    /* ADD THE OVERFLOW */
    overflow-x: hidden;
    overflow-y: visible;
}

#container{
    position: absolute;
    top: 30px;
    left: 20px;
}

#x {
    width: 150px;
    height: 10px;
    background: #c1ffb2;
}

#y {
    width: 10px;
    height: 150px;
    background: #c4b2ff;
    position: absolute;
    left: 20px; /* margin+padding */
    top: 30px; /* margin+padding+x-height */
}

Answer 2

Here's what I have, and it works:

#box {
    position:absolute;
    width: 100px;
    height: 100px;
    margin: 10px;
    background: #ededed;
    padding: 10px;

    /* ADD THE OVERFLOW */
    overflow-y:visible;
    overflow-x:hidden;

}

#x {
    width: 150px;
    height: 10px;
    background: #c1ffb2;
}


#y {
    width: 10px;
    height: 150px;
    background: #c4b2ff;
    position: fixed;
}