After a bit of tinkering, I think I have it working a little closer to what is wanted until I can rebuild things again.
How do I set the z-index higher so that the menu drops above the picture?
select the container "main-menu'
go to layout
go to position
change the position to "relative'
open z-index
select No Units
maybe 500px will do it
This caused a white area over the picture, but no menu.