====== Handling Key Events ======
  * any subclass of NSResponder can accept events

===== key events from NSWindow =====
  * subclass NSWindow, with MyWindow
  * in IB, set the window to use the custom class, MyWindow
  * override the following method in MyWindow:<code objc>
- (void)keyDown:(NSEvent *)event
{
	switch ([event keyCode]) {
		case 121:{ // page down
			if([event modifierFlags] & NSCommandKeyMask) // only do something if the command key was also pressed
				// do something
			break;
		}
	}
}
</code>


===== key events from a custom view =====
  * make the view the first responder
    * there may be a better way to do this, but you can use this:<code>
[view becomeFirstResponder];

or

[window makeFirstResponder:view];
</code>
  * override the keyDown method in the view (see NSWindow above for example)