This is a very good sample source code on Mac. It shows how to customize the NSSavePanel

CustomSave
..........\CustomSave.app
..........\..............\Contents
..........\..............\........\Info.plist
..........\..............\........\MacOS
..........\..............\........\.....\CustomSave
..........\..............\........\PkgInfo
..........\..............\........\Resources
..........\..............\........\.........\English.lproj
..........\..............\........\.........\.............\InfoPlist.strings
..........\..............\........\.........\.............\MainMenu.nib
..........\..............\........\.........\.............\............\classes.nib
..........\..............\........\.........\.............\............\info.nib
..........\..............\........\.........\.............\............\objects.nib
..........\..............\........\.........\.............\MyDocument.nib
..........\..............\........\.........\.............\..............\classes.nib
..........\..............\........\.........\.............\..............\info.nib
..........\..............\........\.........\.............\..............\objects.nib
..........\..............\........\.........\ReadMe.rtf
..........\CustomSave.xcodeproj
..........\....................\project.pbxproj
..........\CustomSave_Prefix.pch
..........\English.lproj
..........\.............\InfoPlist.strings
..........\.............\MainMenu.nib
..........\.............\............\classes.nib
..........\.............\............\info.nib
..........\.............\............\objects.nib
..........\.............\MyDocument.nib
..........\.............\..............\classes.nib
..........\.............\..............\info.nib
..........\.............\..............\objects.nib
..........\Info.plist
..........\main.m
..........\MyDocument.h
..........\MyDocument.m
..........\ReadMe.rtf

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