gistfile1.m

NSNumber *windowLevelIndex = [[NSUserDefaults standardUserDefaults] objectForKey:@"DesktopBackgroundLevel"];
if (windowLevelIndex != nil) {
	switch ([windowLevelIndex integerValue]) {
		case 0: // Show behind the desktop icons, but on the desktop - ignored by Exposé
			[window setLevel:kCGDesktopWindowLevel];
			[window setIgnoresMouseEvents:YES];
			[window orderBack:self];
			break;
		case 1: // Show above the desktop icons - still ignored by Exposé
			[window setLevel:kCGDesktopIconWindowLevel];
			[window setIgnoresMouseEvents:NO];
			[window orderFront:self];
			break;
		default:
			break;
	}
}

[window clearExposeTags];