Can't change text in message body

I am using Payment Form version 6.0.1. When I go into the Configuration and try to change the text on the Messages tab, it won't let me type in the body fields. I can type in the Subject fields and the fields at the top, but not any of the body fields.

Strange. What editor you are using? Tiny MCE? Maybe try to switch to use a different editor?

Or use a different browser like Google Chrome?

Tuan