I am using GNUstep on an Ubuntu 8.04 system, installed using the GNUstep Startup package version 0.20.0. I am trying to complete the first exercise proposed by A. Hillegass in chapter 6 of his book "Cocoa programming for Mac OS X" (third edition). The exercise asks to write a delegate for a window that answers the "windowWillResize:toSize:" message.

It seems that GNUstep never calls this method. Here is the interesting part of the AppDelegate class I implemented (mainWindow is a pointer to the NSWindow I am resizing, its delegate has been set using Gorm):

- (NSSize) windowWillResize: (NSWindow *) window
                     toSize: (NSSize) proposedFrameSize
{
    NSLog (@"windowWillResize:toSize: called");
    return proposedFrameSize;
}

- (void) windowDidResize: (NSNotification *) aNotification
{
    NSLog (@"windowDidResize: called");
}

- (void)applicationWillTerminate:(NSNotification *)aNotif
{
    NSLog (@"Is the window's delegate correct? %d",
           [mainWindow delegate] == self);

    SEL selector = @selector (windowWillResize:toSize:);
    NSLog (@"Does it respond to windowWillResize:toSize? %d",
       [[mainWindow delegate] respondsToSelector: selector]);
}

This is the log I get when I try to resize "mainWindow" and then close the application:

2008-08-18 07:11:48.975 WindowWillResizeTest[14827] Ignore bottom offset change from 32 to 9
2008-08-18 07:11:48.976 WindowWillResizeTest[14827] Reparent was with offset 0 23
2008-08-18 07:11:48.976 WindowWillResizeTest[14827] Parent border,width,height 1,313,320
2008-08-18 07:11:52.579 WindowWillResizeTest[14827] windowDidResize: called
2008-08-18 07:11:53.513 WindowWillResizeTest[14827] Is the window's delegate correct? 1
2008-08-18 07:11:53.513 WindowWillResizeTest[14827] Does it respond to windowWillResize:toSize? 1

As you can see, there is a log message printed by windowDidResize but nothing from windowWillResize, despite the selector being correct.

I am using the default backend installed by GNUstep Startup:

$ defaults read NSGlobalDomain GSBackend
NSGlobalDomain GSBackend libgnustep-back

The full application source is attached.