a process uses a PDF form (not XDP), because the form has digital signature fields. It has several User steps, the input and output of these User tasks is a Document variable.
Before each User submits the form (by clicking an Action button in the WorkSpace window), I want to check the form to make sure the section on the form (that this user is responsible for) does not have errors.
If it has error, I want to pop up a message and prevent the user from submitting the form.
When the form is an XDP and the input-output is an XML variable, I use a hidden flag field to store the name of each User step; the field value is set by the Process map.
But that technique doesn't seem to work when the form is PDF....