A resposta curta: Não. A resposta longa: leia este post de Steve Yegge, que investiga muito da filosofia de design do Mac e suas tentativas de tentar ativar o x-mouse em seu Mac.
Enquanto a ativação de x-mouse (focus-follows-mouse) faz o que você pretende fazer, aparentemente não é suportado neste momento. Eu recomendo o Linux. Termino com esta citação do post referenciado:
Apple OS engineers don't want you to do stuff that they don't want you to do, and they specifically define "stuff they don't want you to do" as "stuff they don't think you want to do." This is actually endemic to Apple forums in general. Whenever someone says "I want focus follows mouse behavior!", some people inevitably reply that "you really don't want to do this". It's that whole "we designed it the right way for everyone" mentality that turns off so many would-be Mac users.