when a mail is composed and the receiver is looked up in the To: field the normal behaviour of Groupwise is to make a suggestion. The user can confirm the suggestion with the tab or the enter key.

For example one types the letters "Fo" and Groupwise makes the suggestion "Foo, Bar" (with "o, Bar" marked) and the user hits the enter key, Groupwise accepts "Foo, Bar" as the receiver.

However, I have one user in which the suggestion is completely ignored. Example: When the user types "Fo" Groupwise suggests "Foo, Bar" as usual. But when the user hits enter or tab Groupwise ignores it's own suggestion and presents a listbox with all names containihng "Fo", e. g. "Foa, abc", "Fob, Def" and even "Othername, Foo123". So the problem is, that the user can no longer confirm Groupwise suggestions with the tab or enter key.

What might have gone wrong here? The user suspects that he accidentally changed the behaviour by hitting some strange keystroke combination.
Note: Name Completition is not disabled

System is Groupwise 8 client with Windows 7 professional 64bit