Bug 94400 [Undo] - After successful undo, should operation be disposed by framework if it cannot be redone?
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
if (DEBUG_OPERATION_HISTORY_UNEXPECTED) {
				System.out
						.print("OPERATIONHISTORY >>> Open operation called while another operation is open.  old: ");  
				System.out.print(openComposite);
				System.out.print("new:  "); 
				System.out.print(operation);
				System.out.println();
			}
			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) {