Cocoa NSRuleEditor:新行的条件

当我在NSRuleEditor中单击某行上的“+”按钮时，将创建一个新行。我如何对该行使用的标准施加影响

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NSRuleEditor似乎默认从可能值列表中依次选择第一个标准。我更希望新行与单击“+”的行匹配。

我可以通过对私有方法进行子类化来伪造它：

- (void)_addOptionFromSlice:(id)slice ofRowType:(unsigned int)type
{
    int rowIndex = [(NSRuleEditorViewSlice*)slice rowIndex];

    NSArray *criteriaForRow = [self criteriaForRow:rowIndex];
    NSArray *displayValuesForRow = [self displayValuesForRow:rowIndex];

    self.template = [NSArray arrayWithObjects:criteriaForRow, displayValuesForRow, nil];

    [super _addOptionFromSlice:slice ofRowType:type];
}

- (void)insertRowAtIndex:(NSInteger)rowIndex withType:(NSRuleEditorRowType)rowType asSubrowOfRow:(NSInteger)parentRow animate:(BOOL)shouldAnimate
{
    [super insertRowAtIndex:rowIndex withType:rowType asSubrowOfRow:parentRow animate:shouldAnimate];

    NSArray *template = self.template;

    if (template != nil) {
        [self setCriteria:[template objectAtIndex:0] andDisplayValues:[template objectAtIndex:1] forRowAtIndex:rowIndex];
    }
}