That's a very interesting suggestion. Right now, this can also be achieved by building a humongous single form that contains all possible pages, but that means implementing tons of conditions, variables, and so on. Not to mention it becomes difficult to work in the design tool when so many objects are present.
My main concern with calling external forms would be performance (both speed and size). Each form contains its own prolog and resources that get cached at the start of the form, but if you call multiple forms (conceivably, some would appear more than once in a single data stream), then you lose that cache and the entire job could become huge and slow.
Perhaps by creating some kind of "shared sub-form" template, we could bypass this issue. That remains to be seen.
I'll certainly keep this suggestion on file. Thanks for your comments and keep them coming!
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Technical Product Manager
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