ProcessChoiceBar is a UIXProcess component that renders a previous button, a choice bar, and a next button.
The processChoiceBar takes a model of type org.apache.myfaces.trinidad.model.MenuModel. The last node along the focusPath and its siblings are rendered.
MenuModel extends TreeModel, but it also knows how to go from the current viewId to the focus path. Notice that the menuModel has no special knowledge of page navigation and places no requirements on the nodes that go into the tree. The nodes in the tree are stamped out with the 'nodeStamp' facet, which should contain a commandNavigationItem component, which allows the default actionListener mechanism to be used for page navigation.