A router state is a subtree of the configuration tree. For instance, the example below has
ConversationsCmp activated. We say activated instead of instantiated as a component can be instantiated only once but activated multiple times (any time its route's parameters change):
Not all subtrees of the configuration tree are valid router states. If a node has multiple children of the same color, i.e., of the same outlet name, only one of them can be active at a time. For instance,
PopupMessageCmp cannot be displayed together, but
PopupMessageCmp can. Stands to reason, an outlet is nothing but a location ...