Hopefully this is a question with a simple answer. I have two SharePoint 2010 environments, each containing a people editor control. In one environment the "check names" button resolves the name into the actual first and last name of the user (e.g. "Fred Smith"). In the other environment, it resolves to the DOMAIN\username format. I am wondering why the difference?
For additional context, the first environment has a user profile application running and syncing with AD. The other has a UPA provisioned, but not syncing. The two environments are also operating in separate domains, so I thought it might have something to do with how AD is configured in the separate domains. Or maybe it's something else entirely?