Bug 362996

If user enters some data into a form in a PDF document, then closes Okular -- data is saved out of band and does not persist with the file. This is reasonable for a "single user/frequently used template" workflow, but not reasonable for "fill out this document and email it back to me" workflow.

Suggestion: if data was edited, upon closing, user should be presented with a choice:
* Save form data in the document
** can be viewed/edited/printed in a different PDF viewer, on another computer, or after file is duplicated
* Remember form data outside the document
** can be viewed/edited/printed from this computer's Okular only

Or the same kind of popup as "this document contains forms" can inform the user that the data can be saved with the file/etc.

The main problem is that user doesn't even know that the data was not saved with the file -- and that there's an option to do that (currently, by Save As)

Reproducible: Always