Making a Button the Default Button

If button has the NSRoundedBezelStyle bezel type, you can mark it as the default button. A default button pulses, and its action message is invoked when the user presses Return. It looks like this:

To mark a button as the default, set its key equivalent to Return with setKeyEquivalent:, like this:

[myButton setKeyEquivalent:@"\r"];

You can also set the button’s key equivalent in Interface Builder, as described in Setting a Button’s Key Equivalent.

The default button has a thick outline drawn around it, outside the button’s border; your interface design should account for that extra space.