App root body vs main/layout

I have created multiple pages for my app. All pages are created in the same way using as type ‘content page’ and for the layout the ‘main’ layout.

But some pages have the app connect set to ‘body’ while other pages are set to ‘layouts/main’.
Why did this happen?

For the pages which are set to ‘body’ I cannot set the security enforcer. So how can I change that page to the ‘layouts/main’ so I can set the security enforcer?

Menno