We have created a Word document with a legacy text form field. We inserted a word date field and protected the document allowing Filling in Forms. After protecting the document when we try going to the form field and clicking on back space to delete the entry we get "This is not a valid selection" message box.

We have existing word documents in 2003 with similar form fields. We were able to delete the entries and add new data. After converting the documents to 2007 or create new documents in 2007 and try to delete the entries we get the above error.