Forum Academy Marketplace Showcase Pricing Features

Floating group 'beneath page' is not showing the elements under the floating group when i preview my page/app

I set my floating group ‘beneath the page’ and put the elements inside of my floating group, but the elements are not visible when am previewing my app page.

what mistake I’m making?

Thank you.

Don’t set it to be “beneath the page”

Why?
please tell me the reason.