One of the greatest improvements (for me) in GW7 WA was the auto propagating of the email addresses when typing a name into the To: field, however that is now gone in GW8 WA.

According to the User Guide:

In the To box, type a username, then press Enter. As you begin to type, the system automatically tries to match the name and complete it for you. Repeat for additional users. If necessary, type user names in the CC and BC boxes.
However that doesn't happen, no matter what name I type nothing propagates into the field. Any ideas why not?