www.wysiwygwebbuilder.com

Try this simple test:

Add layout grid
Under Style give it a solid color
Make padding bottom 50
Add 2nd layout grid
Under Style give it a different solid color
Make padding bottom 50
Preview and see 2 solid bars
On first layout grid change position to header(fixed)
Preview and see only first solid bar
On second layout grid make top margin 50
Now see both bars (and now as you add more objects header stays fixed)
Question - why is it necessary to add the margin on the second grid? In design, you now see a space between the two.

A fixed layout grid will not affect other floating content in HTML, because it's not part of the document flow.

Understood but can the designer reflect that?

The current behavior is intentionally, otherwise the first floating layer or layout grid falls behind the fixed header and then you can now longer access it to change the properties.

OK thanks.