Issues with Bento should be reported in the Bento Forums. This forum section is for reporting possible bugs with FileMaker GO, FIleMaker Server or FileMaker Pro.
Thank you for your post.
Bento does not have a default option for a Choice field. If you are unable to change the value, are you sure it is a Choice field and not a Calculation field?
Also, make sure the Choice field is not similar in name to another field. For example, I had a file sent to me yesterday that had the fields "Order#" and "Order #".
In the future, please post your question to the Bento forum at: