Objective-c: NSButton setAction не работает

Я делаю пару кнопок программно и пытаюсь установить действие для каждой, но, кажется, не могу заставить ее работать.

В моем AppController.h у меня есть этот код:

...
IBOutlet NSButton* btnZoomIn;
IBOutlet NSButton* btnZoomOut;
...

и

- (IBAction) zoomIn : (id) sender; 

- (IBAction) zoomOut : (id) sender;

и в AppController.m внутри метода awakeFromNib:

/*zoom in and out buttons*/

//get the path to the image files
NSString* zoomInImgPath = [[NSBundle mainBundle] pathForResource:@"zoomIn" ofType:@"png"];
NSString* zoomOutImgPath = [[NSBundle mainBundle] pathForResource:@"zoomOut" ofType:@"png"];

//declare the NSImages
zoomInImg = [[NSImage alloc] initWithContentsOfFile:zoomInImgPath];
zoomOutImg = [[NSImage alloc] initWithContentsOfFile: zoomOutImgPath];

//button making!
//zoomIn
btnZoomIn = [[NSButton alloc] initWithFrame:NSMakeRect(1426.0, 920.0, 25.0, 25.0)];
[btnZoomIn setButtonType:NSMomentaryPushInButton];
[btnZoomIn setTitle:@""];
[btnZoomIn setToolTip:@"Zoom In"];
[btnZoomIn setImage:zoomInImg];
[btnZoomIn setAction:@selector(zoomIn:)];
[[mainWin contentView] addSubview:btnZoomIn];

//zoomOut
btnZoomOut = [[NSButton alloc] initWithFrame:NSMakeRect(1456.0, 920.0, 25.0, 25.0)];
[btnZoomOut setButtonType:NSMomentaryPushInButton];
[btnZoomOut setTitle:@""];
[btnZoomOut setToolTip:@"Zoom Out"];
[btnZoomOut setImage:zoomOutImg];
[btnZoomOut setAction:@selector(zoomOut:)];
[[mainWin contentView] addSubview:btnZoomOut];

и

- (IBAction) zoomIn : (id) sender  { 
    NSLog(@"zoom in!");
 }

 - (IBAction) zoomOut : (id) sender { 
    NSLog(@"zoom out!");
 }

, но zoomOut и zoomIn не попадает...