MS Word Form Creation - Responders Can't Enter Text

I have created a survey form in MS Word 2013 that will be used by students to rate a class that they take. I've used Active X controls (option buttons) for the ratings (e.g., great, good, bad, awful) and a rich text content control for students to put comments in. When I take the form out of Design mode, all of the option buttons work as they should and the rich text control works properly. When I set editing restrictions to filling in forms via the Restrict Editing option, however, responders, while still able to choose options, are then unable to enter anything into the rich text control (question 5 on the form).

I do want to protect the document so that responders can not modify anything on it but I do want them to be able to answer the questions, including the text question.

Can someone help me with this?

I've attached a sample copy of the survey (not restricted). It is attached as a docx file because that is all that EE will accept. It is actually a .docm file.
Training-Survey.docx