I'm trying to understand the relationship between forms created for a Content Type, and how that form manifests itself on a List that uses that Content Type.
In my specific example, on the Content Type form I wanted to display this calculated control:
Published on: {ItemProperty:Created}
However, when authoring the Content Type form, it has no notion of Item Properties -- not even the built-in ones (Created, Created by, etc) -- so this is not possible. I then thought if I edit the form on the List where it's being used, I can then access the Item Properties and include this calculated control. And what do you know? It worked!
In my mind, I assumed that I had now created an instance (or customised version) of the Content Type form in my list. But when I went and updated the Content Type form again, I had lost the customisation to the form on the List.
So what's happening here? If forms for Content Types cannot be customised, why allow the user to even modify it at the list level? Or why can't built-in Item Properties be accessed in the Content Type form editor?