Claris Resolve shares some technology with Wingz by Informix. In Wingz, you can use menu commands to place borders around the report header and footer. Although Claris Resolve doesn't give you menu commands to accomplish this, you can use two script commands instead.
To use these commands, just type them into the entry bar and press Command-Return. This tells Resolve to consider your entry as a command to be executed immediately, not a cell value or formula.
To turn on header borders, type:
select report header single line border
To turn off header borders:
select report header no line border
You can substitute footer for header and double for single if you like.