Protecting a Word document

[Farsideout]

I am trying to protect a Word document with form fields so that the fields can be edited and the rest of the document protected. I have applied a password, choosing the 'allow form filling option' and having done that the document behaves correctly.

However, once saved and closed and reopened again I can uprotect the document without being asked to enter the password. I am using Word 2003 but the same thing happens in 2007.

Can anyone help please?

Thanks