NSMatrix, NSForm - addRow - why above and not below?

Question

I'm running into a strange behavior with NSForm (and also NSMatrix).

(1) Using interface builder (in Xcode 4.3.1) I place an NSForm in a window. I add a NSButton and wire it to an IBAction that sends addRow to the NSForm.

- (IBAction) addRow:(id)sender
{
    [form addRow];

    [form sizeToCells];
}

The problem is that the new row is added ABOVE the existing row, not below as it's supposed to. I thought this was a problem coming from somewhere else in my app, but I created a new project in Xcode and this happens even in the simplest app.

I must be doing something stupid wrong, but I can't find it. Any suggestions would be appreciated.

Answer 1

[form setFrameOrigin:NSPointFromCGPoint(CGPointMake([radioButtons frame].origin.x, [radioButtons frame].origin.y-20))];