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 (DEBUG_OPERATION_HISTORY_UNEXPECTED) {
				if (openComposite == null) {
					Tracing.printTrace("OPERATIONHISTORY", 
							"Attempted to close operation when none was open"); 
					return;
				}
			}
			
			if (openComposite != null) {
				if (DEBUG_OPERATION_HISTORY_OPENOPERATION) {
					Tracing.printTrace("OPERATIONHISTORY", "Closing operation " 
							+ openComposite);
				}
				endedComposite = openComposite;
				openComposite = null;
			}
		}
		
		
		
		if (endedComposite != null) {
			if (operationOK) {
				if (mode == EXECUTE)
					notifyDone(endedComposite);
				if (addToHistory)
					add(endedComposite);
			} else {
				if (mode == EXECUTE)
					notifyNotOK(endedComposite);
			}