I have a similar problem as Stackoverflow.com web site has. The problem is width a banner above the content or body of the web site. I want to be able to reduce the width of the browser page but keep the size of the banner no matter what resolution is running the browser.
Example, if you reduce the width of this page you will see that a scroll bar will appear so you can move the page to the right and see the content hide. However, if you look at the banner the banner will have the new width that was reduced the page.

If i understand correctly may be you can define min-width in to the body. Write like this:
It’s mostly happened when the element have auto width & his parent didn’t have any
widthdefine.