Bug 105697 [Undo] - OperationHistoryEvent - cannot distinguish between canceled event or failed event
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
* Remove the operation by disposing it and notifying listeners.
	 */
	private void internalRemove(IUndoableOperation operation) {
		operation.dispose();
		notifyRemoved(operation);
	}
	/*
	 * Notify listeners of an operation event.
	 */
	private void notifyListeners(OperationHistoryEvent event) {
		preNotifyOperation(event.getOperation(), event);
		
		
		
		final IOperationHistoryListener[] listenerArray = (IOperationHistoryListener[]) listeners
				.toArray(new IOperationHistoryListener[listeners.size()]);
		for (int i = 0; i < listenerArray.length; i++)
			try {
				listenerArray[i].historyNotification(event);
			} catch (Exception e) {
				handleNotificationException(e);
			}
	}
	private void notifyAboutToExecute(IUndoableOperation operation) {
		if (DEBUG_OPERATION_HISTORY_NOTIFICATION) {
			System.out.print("OPERATIONHISTORY >>> ABOUT_TO_EXECUTE ");  
			System.out.print(operation);
			System.out.println();
		}
		notifyListeners(new OperationHistoryEvent(