Bug 249574 [Contributions] ExternalActionManager.addPropertyChangeListener() doesn't register the ListenerList
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ExternalActionManager.java
* @param listener
		 *            The listener to be added; must not be <code>null</code>.
		 */
		public void addPropertyChangeListener(String identifier,
				IPropertyChangeListener listener);
		/**
		 * An accessor for the accelerator associated with the item indicated by
		 * the identifier. This identifier is specific to mechanism being used.
		 * In the case of the Eclipse workbench, this is the command identifier.
		 * 
		 * @param identifier
		 *            The identifier of the item from which the accelerator
		 *            should be obtained ; must not be <code>null</code>.
		 * @return An integer representation of the accelerator. This is the
		 *         same accelerator format used by SWT.
		 */
		public Integer getAccelerator(String identifier);
		/**
		 * An accessor for the accelerator text associated with the item
		 * indicated by the identifier. This identifier is specific to mechanism
		 * being used. In the case of the Eclipse workbench, this is the command
		 * identifier.
		 * 
		 * @param identifier
		 *            The identifier of the item from which the accelerator text
		 *            should be obtained ; must not be <code>null</code>.
		 * @return A string representation of the accelerator. This is the
		 *         string representation that should be displayed to the user.
		 */
		public String getAcceleratorText(String identifier);