Subform not working in edit?

By having a master / detail schema like invoices for example, the subform option is great!
But … it only works in add, when editing the subform no longer appears.
I am with radsystems 4.0 nodejs.

@ddiaz, I assume you are referring to the edit page. I noticed too that the SubForm option is missing in the Edit Page Properties.

I would like to see this option for the Edit page too.