Different behaviour between Firefox and Chrome using relative position CSS

I need some help to try and develop a workaround for a CSS problem I am having.  My problem is that I have some code that works perfectly in Firefox, but the page renders slightly differently in Chrome and Safari and causes a problem.

Difficult to explain my problem, but I will try.  I have a div called #pageoptions and it displays perfectly fine in Firefox.

Here is the CSS:

#pageoptions {
position: relative;
overflow: hidden;
width: auto;
padding: 0;
min-height: 20px;
}

For some reason, when I begin typing in a certain input box in Chrome, it causes this div move and become partly visible.  When I do the same thing in Firefox, the div does not move at all and remains put as it should.

I know this is not a very good description, but hopefully it is enough to give you an idea of where I am stuck.  Any ideas would be appreciated.