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
}
	
				throw new IllegalStateException(
						"Cannot open an operation while one is already open"); 
			}
			openComposite = operation;
		}
		if (DEBUG_OPERATION_HISTORY_OPENOPERATION) {
			System.out.print("OPERATIONHISTORY >>> Opening operation ");  
			System.out.print(openComposite);
			System.out.println();
		}
		if (mode == EXECUTE) {
			notifyAboutToExecute(openComposite);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IOperationHistory#closeOperation(boolean,
	 *      boolean)
	 */
	public void closeOperation(boolean operationOK, boolean addToHistory,
			int mode) {
		ICompositeOperation endedComposite = null;
		synchronized(openCompositeLock) {
			if (DEBUG_OPERATION_HISTORY_UNEXPECTED) {
				if (openComposite == null) {
					System.out
							.print("OPERATIONHISTORY >>> Attempted to close operation when none was open ");