I can't figure out how to get rid of these lines between records. None of the records are set up for Primary, ALternative or Active (Body part).
Here are two snapshots.
One shows a Layout where no lines show up.
The other shows where the lines show up.
I found the answer.
I had a white box locked, at the top, running full width. And behind it was a grey line, which was just over the Header border.
But since I could not see this grey line buried below (I had forgotten it was there), it couldn't understand where the grey line was coming from.