A family of Microsoft word processing software products for creating web, email, and print documents.
Assuming that the form is protected, pasting outside the fields shouldn't be possible. Does the problem occur when you paste large pieces of text only? In that case, what you are seeing is probably normal: the pasted data pushes the existing content out of the way (as with any paste operation, even in unprotected documents), which would affect the layout of the entire form. To prevent this from happening, the form must be designed so that fields are inside table cells whose dimensions are fixed.