Hi Frank,
This is not out of box behavior, so you'll have to see if the UI Action has already been modified in your instance, or if a Client Script or Business Rule was put in place to set a close code when the State changes to resolve. You can test this if you are able to change the State to Resolve manually - if the close code populates, then it's probably not included in the UI Action script, so check Client Scripts and Business Rules on the incident or task table with a set action or script. This could also be in a script UI Policy. If the close code doesn't populate with a manual State change, then check the The UI Action record named Resolve on the incident table. In the Script you should see where the current value is being set.
