Thank you for your post.
I am able to replicate the problem only on Windows (XP, Vista, and 7). It works correctly on Mac OS X 10.5.8 (Leopard) and 10.6.2 (Snow Leopard).
In addition, I have discovered that when I make the Header and Body the same fill color, the field becomes obscured when I select a field in the Body. If no field is selected, all fields display properly.
I have forwarded your post along with my findings to our Development and Software Quality Assurance (Testing) departments for review and confirmation. When more information becomes available, I will let you know.