A problem occurred with a client of mine. An odd, frustrating large prompt every time she typed in an email address. I had to dig around for awhile before I found out how to disable this functionality.
The Secret: Right click the To: field entry box. Uncheck Search Mode.
Not a place I would normally expect a menu option such as this. Which makes this kind of problem a nuisance. Hope this helps others! Considering this is bound to a couple common keys (ctrl + enter) I can see why this would happen every now and then in a GroupWise environment.