My form only allows me to edit certain parts of the form, but not other

My form only allows me to edit certain parts of the form, but not other parts. I have an entry form and am trying to change a category which someone entered. I'm wondering if it's because there is a fee associated with the category and the person who submitted it already paid. The change I'm trying to do wouldn't change the amount owed, if that makes a difference.

It is not possible to edit any data that your users entered inside of a payment filed. 

If your issue is not related to the payment field, please provide us a form URL, and tell us to exactly which field is the issue related to.