When installing the same extension on differents namespaces only one listener will be registered

The same root ObservationManager is generally used for all listeners of all namespaces (wikis).

Because both obviously have the same id, ObservationManager complain that we are trying to register twice the same listener an only keep one.

Problem is that only one of the namespace (wiki) will have its extension receive events.

A workaround is to generate a unique id (for example using System.identityHashCode(this)) in getName().