Header lines in widgets appearing on the page

Hi

I am building out a page layout in a group, and I noticed that header borders are being shown on screen: 

I guess I don't mind them appearing when I use the header field (as seen in the left-hand column), but when I don't want to use the header field in a widget then I don't want to see the line (the main column). Is there any way to remove this line when not using the header field in a widget?

Thanks

Oli



Image broke on upload, re-added.
[edited by: Oliver Beirne at 12:09 PM (GMT 0) on Tue, Mar 16 2021]