IMO, it depends how "connected" and "coupled" you want your components.
Having 3 display regions, you have very specialized and loosely coupled
activities, and they have to communicate through events on the event bus.
With a single display region, you have a more complex activity but its inner
I am facing a dilemma best explained using a concrete example.
Look at the *New* Google Group application. (taking gwt group as an example)
when we are in the main place: #!forum/google-web-toolkit
there is a display region/activity to the left, which holds Home/Favorite
a display region/activity
