The selection of directory service properties is disabled because the portal is in an untrusted domain

In User Profile, I was unable to modify any user property mapping due to missing Data Source field dropdown. There was no question of untrusted domain as I am using only one active directory and SharePoint was able to import from that. I finally managed to fix these by following these steps:

• Goto to Profile and Import Settings
• Click View Import Connections
• Click on Existing Import Connection and select edit
• In Authentication Information section, make sure the account is SharePoint Admin Domain account and not the default account
• Click Ok and you should now able to see mapping data source drop down