In GWT app where one has multiple presenters rendering views based on user actions/events, I have certain questions wrt MVP
1) What is the best way to pass data between multiple presenters. For example one presenter needs to pass a String or any other Object to other presenter. Of course the method should be such that presenters are still decoupled
2) For navigation around multiple presenters/views should one use Events or History or Both? Is there any specific drawback of using only History tokens and not having events
Passing complex information between presenters is done best via events.
However I wouldn't completely neglect History.
If you want to support bookmarks and allow the user to load/go back to a specific application state/view you have to use History.
You might use a hybrid approach between Activity/Places and Custom Events.