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Form B's from schema document is in the same namespace as form A's since we added the same XSD data source to both. So the values entered into form A's fields will be used as an initial instance document to initialize form B's fields. Refer to Multi page forms for the details about posting data between forms using Form Action wizards.
See default field values to understand the precedence that XML documents sent in the Post request to form B take over the other possible methods of defaulting form field values.
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