Retain the review materials section heading when scrolling a long list of files.

The section "Review Materials" becomes unreadable/unusable if you have several objects added and a lot of comments/defects are existing. When scrolling down, the heading of the table disappears, and you can't see the reviewers' names anymore, so you don't know who was the submitter of which comment/defect unless you either scroll back upwards or open the single comment