Sub-classes of java.awt.Component (including Swing) always call
firePropertyChange even if there are no listeners because there
is no way for these classses to know this. However, supporting change
notification is expensive because the values passed in the
notification are often cloned or duplicated, even if they
are composite values or containers (arrays, vectors, hashtables).
It should be possible for sub-classes of java.awt.Component to
efficiently determine if property change-notification is necessary
_before_ constructing these duplicate values (see Suggested Fix).
Accessible property changes could also be lazy.