NSToolbar created programmatically starts empty and won't save - objective-c

Question

I'm currently trying to write a Mac application. In doing so, I'm having some peculiar problems when trying to setup an NSToolbar.
Although I have setup all the components as per the API documentation, when the application loads, the toolbar always starts empty. When I open the customisation pane, the toolbar items are there, and I can drag them into the toolbar, but when I quit the application and restart the changes are gone.
Note: I am aware that many of you will be of the opinion that the best way to solve this is to use interface builder rather than doing it in code. That is not the answer I am looking for - I chose to make this application without IB in order to better understand the internals of a Cocoa app.
I have verified (with NSLogs) that neither the toolbarAllowedItemIdentifiers nor the toolbarDefaultItemIdentifiers delegate methods get called when the toolbar is first initialised, but they do get called when you enter the customisation pane.
Below, please find a minimal, verifiable and complete example version of a basic app that demonstrates this bug. Anyone that can shed some light on this matter would be hugely appreciated!
Thanks
Defines.h
#define UNUSED(x) (void)(x)
#define TOOLBAR_ONE #"ONE"
#define TOOLBAR_TWO #"TWO"
#define TOOLBAR_IDENT #"TOOLBAR"
#define WINDOW_MASK NSTitledWindowMask | \
NSClosableWindowMask | \
NSResizableWindowMask | \
NSMiniaturizableWindowMask
main.m
#import "BWAppDelegate.h"
#import <AppKit/AppKit.h>
int main(void) {
#autoreleasepool {
NSApplication* application = [NSApplication sharedApplication];
BWAppDelegate* delegate = [[BWAppDelegate alloc] init];
application.delegate = delegate;
[application run];
return EXIT_SUCCESS;
}
}
BWAppDelegate.h
#import <Cocoa/Cocoa.h>
#import "BWMainToolbarDelegate.h"
#interface BWAppDelegate : NSObject<NSApplicationDelegate>
#property (atomic, strong) NSWindow* window;
#property (atomic, strong) BWMainToolbarDelegate* toolbarDelegate;
#end
BWAppDelegate.m
#import <AVFoundation/AVFoundation.h>
#import <AppKit/AppKit.h>
#import <Cocoa/Cocoa.h>
#import "BWAppDelegate.h"
#import "Defines.h"
#implementation BWAppDelegate
#synthesize window, toolbarDelegate;
- (void) applicationDidFinishLaunching: (NSNotification*) aNotification
{
UNUSED(aNotification);
NSRect dims = NSMakeRect(0, 0, 300, 300);
self.window = [[NSWindow alloc] initWithContentRect:dims
styleMask:WINDOW_MASK
backing:NSBackingStoreBuffered
defer:NO];
[self.window makeKeyAndOrderFront:nil];
self.window.toolbar = [[NSToolbar alloc] initWithIdentifier:TOOLBAR_IDENT];
toolbarDelegate = [[BWMainToolbarDelegate alloc] initWithToolbar:self.window.toolbar];
}
#end
BWMainToolbarDelegate.h
#import <AppKit/AppKit.h>
#import <Foundation/Foundation.h>
#interface BWMainToolbarDelegate : NSObject<NSToolbarDelegate>
- (instancetype) initWithToolbar: (NSToolbar*) theToolbar;
- (NSArray*) toolbarAllowedItemIdentifiers: (NSToolbar*) toolbar;
- (NSArray*) toolbarDefaultItemIdentifiers: (NSToolbar*) toolbar;
- (NSToolbarItem*) toolbar: (NSToolbar*) toolbar
itemForItemIdentifier: (NSString*) identifier
willBeInsertedIntoToolbar: (BOOL) flag;
#end
BWMainToolbarDelegate.m
#import "BWMainToolbarDelegate.h"
#import "Defines.h"
#implementation BWMainToolbarDelegate {
NSToolbar* toolbar;
}
- (instancetype) initWithToolbar: (NSToolbar*) theToolbar
{
self = [super init];
if(self) {
toolbar = theToolbar;
toolbar.displayMode = NSToolbarDisplayModeIconAndLabel;
toolbar.allowsUserCustomization = YES;
toolbar.autosavesConfiguration = YES;
toolbar.delegate = self;
}
return self;
}
- (NSArray*) toolbarAllowedItemIdentifiers: (NSToolbar*) theToolbar
{
UNUSED(theToolbar);
return #[TOOLBAR_ONE, TOOLBAR_TWO];
}
- (NSArray*) toolbarDefaultItemIdentifiers: (NSToolbar*) theToolbar
{
UNUSED(theToolbar);
return #[TOOLBAR_ONE, TOOLBAR_TWO];
}
- (NSToolbarItem*) toolbar: (NSToolbar*) theToolbar
itemForItemIdentifier: (NSString*) identifier
willBeInsertedIntoToolbar: (BOOL) flag
{
UNUSED(flag);
NSToolbarItem* returnVal = nil;
NSString* label;
if([theToolbar.identifier isEqualToString:TOOLBAR_IDENT]) {
if([identifier isEqualToString:TOOLBAR_ONE]) {
returnVal = [[NSToolbarItem alloc] initWithItemIdentifier:TOOLBAR_ONE];
label = #"Toolbar One";
} else if([identifier isEqualToString:TOOLBAR_TWO]) {
returnVal = [[NSToolbarItem alloc] initWithItemIdentifier:TOOLBAR_TWO];
label = #"Toolbar TWO";
}
}
returnVal.label = label;
returnVal.paletteLabel = label;
return returnVal;
}
#end

Answer 1

Set the delegate of the toolbar before adding the toolbar to the window.