Not sure if this will solve your problem, but it is worth a try if you don’t find a better solution. Instead of using traditional child pages I create junction pages that use page includes for my child pages. This allows you to keep using the children pages with or without the header so you can display them either way. Example: -Master page name: MasterHeader -Existing stand along page name: ContactDetail -Create a new child page named: ContactDetailWithHeader that is a child of MasterHeader -add a page include to ContactDetail in your new ContactDetailWithHeader Page and pass in any URL Parameters needed.
