Bug 172765 [DataBinding] Consistency when registering property change listeners
bundles/org.eclipse.core.databinding.beans/src/org/eclipse/core/internal/databinding/internal/beans/ListenerSupport.java
public void unhookListener(Object target) {
		if (target.getClass()==IdentityWrapper.class)
			target = ((IdentityWrapper)target).unwrap();
		
		Method removePropertyChangeListenerMethod = null;
		try {
			removePropertyChangeListenerMethod = target.getClass().getMethod(
					"removePropertyChangeListener", 
					new Class[] { PropertyChangeListener.class });
		} catch (SecurityException e) {
			
		} catch (NoSuchMethodException e) {
			
		}
		if (removePropertyChangeListenerMethod != null) {
			try {
				removePropertyChangeListenerMethod.invoke(target,
						new Object[] { listener });
				elementsListenedTo.remove(new IdentityWrapper(target));
				return;
			} catch (IllegalArgumentException e) {
				
			} catch (IllegalAccessException e) {
				
			} catch (InvocationTargetException e) {
				
			}
		}
	}