Bug 184597 [Contributions] ActionContributionItem should show accelerator text even if accelerator cannot be parsed
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ActionContributionItem.java
widget = ti;
			update(null);
			
			action.addPropertyChangeListener(propertyListener);
			if (action != null) {
				String commandId = action.getActionDefinitionId();
				ExternalActionManager.ICallback callback = ExternalActionManager
						.getInstance().getCallback();
				if ((callback != null) && (commandId != null)) {
					callback.addPropertyChangeListener(commandId,
							actionTextListener);
				}
			}
		}
	}
	/**
	 * Returns the action associated with this contribution item.
	 * 
	 * @return the action
	 */
	public IAction getAction() {
		return action;
	}
	/**
	 * Returns the listener for SWT button widget events.
	 * 
	 * @return a listener for button events
	 */
	private Listener getButtonListener() {
		if (buttonListener == null) {