Bug 123316 [Undo] - API BEHAVIOR - should always place a successfully undone/redone op on the redo/undo history
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
if (status.isOK()) {
			notifyAboutToUndo(operation);
			try {
				status = operation.undo(monitor, info);
			} catch (OperationCanceledException e) {
				status = Status.CANCEL_STATUS;
			} catch (ExecutionException e) {
				notifyNotOK(operation);
				if (DEBUG_OPERATION_HISTORY_UNEXPECTED) {
					Tracing.printTrace("OPERATIONHISTORY", 
							"ExecutionException while undoing " + operation); 
				}
				throw e;
			} catch (Exception e) {
				notifyNotOK(operation);
				if (DEBUG_OPERATION_HISTORY_UNEXPECTED) {
					Tracing.printTrace("OPERATIONHISTORY", 
							"Exception while undoing " + operation); 
				}
				throw new ExecutionException(
						"While undoing the operation, an exception occurred", e); 
			}
		}
		
		
		if (status.isOK()) {