Is it possible for NSDatePicker natively enable functionality to show graphical implementation in popover when changing date? Such functionality now exists in OS X Calendar and Reminders.
Or I need to implement such functionality by myself? If so, maybe there are such third party implementations?
You can create a popover and place an NSDatePicker inside it, then in Interface Builder choose for the NSDatePicker to be graphical. That's really all there is to it, but perhaps you need to clarify the question if there's more to what you're expecting.