When I select hello then press cmd + e, which puts the world "hello" into my search filter. If I then decide I want to search for something else I would select a different word world then do cmd + e. In Xcode and other OS X apps, pressing cmd + e would replace the search filter from "hello" to "world". In AppCode it changes it to "hello|world" highlighting both options.
I can't find an option or setting for changing this to be more OS X-like, any ideas? ( tested in 3.1 EAP )