Cannot force <DIV> to be on one line

[ppowell777]

My <DIV> block needs to display on a single line but refuses to do so:

<div class="header" style="white-space: nowrap; overflow: hidden">
    // content
</div>

It uses an existing CSS class that is currently failing to display the <DIV> as a single line of content:

.header {
    z-index: 200;
    line-height: 40px;
    position: absolute;
    top: 0;
    right: 3px;
    padding: 2px 0;
    text-align: right;
}

I added the style attribute myself, thinking that would force the <DIV> content to align to only one line, but it had no effect.

What else do I need to do?

Thanks