Vaadin 6 portlet lifecycle between portlet page navigations

This might be a WebSphere 6.1 specific question but would like to know what the lifecycle of a porltet is when navigating between Portlet Pages.

For example on the Home Page we have one Vaadin portlet deployed. If the user navigates to another portlet deployed on a different Porlet Page and the returns to the original Home Page do they see the original instance of the Vaadin Application or is a new fresh one created? Is the application cached in the Portlet Session until the session expires?

Can this behavior be controlled? Is this configurable? Is this platform specific or generic for all portlet engines?

If the same instance is cached is there a way to trigger off a porlet reload event to keep data up to date?