To be able to help we need to reproduce the problem. Without more information, the only thing I could suggest is to ensure that you are using XHTML-compliant Doctype on the parent and content pages
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
and the following CSS in the content page:
html, body, form
If the suggestions above don't help, please try isolating this behavior in a sample project and send it to us - we will check it right away.
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