String (int index) { if (myRulesModel.getSize() < index) { return null; } final Object target = myRulesModel.getElementAt(index); if (target instanceof StdArrangementMatchRule) { for (int i = 0; i < index; i++) { final Object element = myRulesModel.getElementAt(i); if (element instanceof StdArrangementMatchRule && target.equals(element)) { return ApplicationBundle.message("arrangement.settings.validation.duplicate.matching.rule"); } } } return null; }