Bug 249574 [Contributions] ExternalActionManager.addPropertyChangeListener() doesn't register the ListenerList
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ExternalActionManager.java
/**
		 * Checks whether the command with the given identifier should be
		 * considered active. This can be used in systems using some kind of
		 * user interface filtering (e.g., activities in the Eclipse workbench).
		 * 
		 * @param commandId
		 *            The identifier for the command; must not be
		 *            <code>null</code>
		 * @return <code>true</code> if the command is active;
		 *         <code>false</code> otherwise.
		 */
		public boolean isActive(String commandId);
	}
	/**
	 * <p>
	 * A callback which communicates with the applications binding manager. This
	 * interface provides more information from the binding manager, which
	 * allows greater integration. Implementing this interface is preferred over
	 * {@link ExternalActionManager.ICallback}.
	 * </p>
	 * <p>
	 * Clients may implement this interface, but must not extend.
	 * </p>
	 * 
	 * @since 3.2
	 */
	public static interface IBindingManagerCallback extends ICallback {