An observer with this signature:

observe(@Observes XEvent event)

is not notified when an event is fired like this:

manager.fireEvent(new XEvent(), new Qualifier1(), new Qualifier2(), ...);

If the observer specifies any of the Qualifiers (or any subset of them, except the empty one), then it's notified.

However, if fired like this:

manager.fireEvent(new XEvent(), new DefaultLiteral(), new Qualifier1(), new Qualifier2(), ...);

with the DefaultLiteral among the qualifiers, then it works as expected.

Firing an event with an Event<XEvent> also works.