In the very first example screenshot on that page, it would appear that the user is presented with three different ways to cancel the action: clicking NO, click

In the very first example screenshot on that page, it would appear that the user is presented with three different ways to cancel the action: clicking NO, clicking CANCEL, or clicking the close box. I would presume they effectively do the same thing? As far as I know this is typical of a Windows dialog box. I'm a Mac user: can someone tell me how this could possibly be considered good UI? BTW, Cancel-OK dates from both of OS X's parents: MacOS and NeXTSTEP.