The user has made below settings at his end:
1. Type-ahead for all names fields is disabled in iNotes preferences.
2. "Name resolution & validation" is set as "Disabled" in the configuration document.
When he types the partial name of the recipient and clicks on "Send", Domino sends a mail after selecting a matching recipient user name on its own.
The requirement of user is to prevent erroneous mail delivery in iNotes to unintended recipients due to similar looking user names