Bug 249574 [Contributions] ExternalActionManager.addPropertyChangeListener() doesn't register the ListenerList
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ExternalActionManager.java
* The binding manager for your application. Must not be
		 * <code>null</code>.
		 */
		private final BindingManager bindingManager;
		/**
		 * Whether a listener has been attached to the binding manager yet.
		 */
		private boolean bindingManagerListenerAttached = false;
		/**
		 * The command manager for your application. Must not be
		 * <code>null</code>.
		 */
		private final CommandManager commandManager;
		/**
		 * A set of all the command identifiers that have been logged as broken
		 * so far. For each of these, there will be a listener on the
		 * corresponding command. If the command ever becomes defined, the item
		 * will be removed from this set and the listener removed. This value
		 * may be empty, but never <code>null</code>.
		 */
		private final Set loggedCommandIds = new HashSet();
		/**
		 * The list of listeners that have registered for property change
		 * notification. This is a map of command identifiers (<code>String</code>)
		 * to listeners (<code>IPropertyChangeListener</code> or
		 * <code>ListenerList</code> of <code>IPropertyChangeListener</code>).
		 */
		private final Map registeredListeners = new HashMap();
		/**
		 * Constructs a new instance of <code>CommandCallback</code> with the