Changing a role to add edit capability

If you look at the field properties for that field and roll down the list of roles, you will probably see that some roles are limited in what they can do (none, view/ edit) . While, this capability to control editing at the field level is powerful, it is somewhat obscure and where possible I try to avoid using that granular control because if you get an app full of these limitations at the field level, it's very hard to maintain.