How to receive keyboard events for a NSView after exiting fullscreen mode?

Question

I subclass an NSView and start full screen mode when the application finished launching. The view is available as the property fooView in the application delegate.

// AppDelegate.m
- (void)applicationDidFinishLaunching:(NSNotification*)notification {
  [[self window] makeKeyAndOrderFront:self];
  [[self fooView] enterFullScreenMode:[NSScreen mainScreen] withOptions:nil];
}

The class FooView itself implements the following functions.

// FooView.m
- (void)keyDown:(NSEvent*)event {
  NSLog(@"%@ %@ - %@", self.className, NSStringFromSelector(_cmd), event);
  [self interpretKeyEvents:[NSArray arrayWithObject:event]];
}
- (void)cancelOperation:(id)sender {
  NSLog(@"%@ %@ - %@", self.className, NSStringFromSelector(_cmd), sender);
  [self exitFullScreenModeWithOptions:nil];
}

After leaving the fullscreen mode, the view no longer receives keyboard events. Why?

Edit:
It seems to have something to do with how I exit the fullscreen mode. When I click into the view (not the window) the keyDown: and cancelOperation: do respond in the following.