When we had created forms using Infopath, if a field was disabled via a rule, a person could still access the value of the field and copy it (Ctrl C) and then paste the value somewhere else. This functionality does not appear to be available Nintex Forms. If there is a rule to disable the field, the field cannot be accessed via the form in any way. People can still access and edit it in a regular Sharepoint list view, but that is not what we want to do.
Is there some way to configure the field to be disabled for edit but available to copy? Or is this a feature of Nintex Forms?
Hmm, what you could possibly do is allow it to be editable, and then disable the save button if NamedControlValue != ItemPropertyValue. It's kind of clunky, but it could work. Or rather, it would be better to have a validation rule applied to the field in question where the field is invalid if namedControlValue != itemPropertyValue, rather than disabling the save button. Then, when you go to "Save" the item, it highlights the field in red and gives your custom error message.