NSButton default button with blueish look

Question

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

Answer 1

My setting has been a custom sheet where I wanted the default button to appear like within an NSAlert. The following configuration gives me the blue default appearance. Works in 10.12.3 Sierra.

   button.bezelstyle = NSBezelStyleRounded; // Push in Interface Builder
   button.keyEquivalent = @"\r";
   button.highlighted = YES; // this is the most important part.