Developers using Swing often encounter the problem of adding a Listener
(typically Mouse or Key) to a Swing Component and notice that they don't
get any notification. The reason this happens with some swing components
(JTabbedPane, JComboBox ...) is because they are composite Components made
up of other Components with Listeners attached to the children, so that if
the Listener is added to the actual Swing component it is not notified because
the children Components have listeners. Swing, or perhaps AWT, should offer
support for such Composite Components that developers want to treat as if they
were not composite components.