The JavaFX event model is such that an Event is delivered to all listeners of the event unless consumed. In order for controls to properly function, most subclasses of Control will consume their input events once processed. We should improve the documentation to make it clear to an application developer that most controls do this, and as such, the application should not expect some events to be delivered to their handler when calling the onXxxxxx method.

See JDK-8095998 and JDK-8163268 for an example where the lack of clarity caused some confusion.