A family of Microsoft word processing software products for creating web, email, and print documents.
If you press Alt+F9, do you see the StyleRef field in the header? If so, then it is working, but it is picking up a blank Heading 1. Search for the Heading 1 style (starting at the top of the document), and you'll likely find an empty paragraph with the Heading 1 style applied. This might be a page break; if that's a problem, use Page Break Before formatting in the heading instead of a manual page break.