title: NSButton default button with blueish look
body: <p>I have a dialog with 1 or more buttons and want to be able to programmatically set the rightmost one be the default one, so that when the user presses the Enter or Return key it should respond as if the user clicked it.</p>
  
  <p>I'm using <code>[btn setKeyEquivalent:@"\r"]</code> and that makes it work fine but I want the button to have the blueish look which isn't happening. What do I need to do?</p>