It is ridiculous to see some people are porting GIMP or Inkscape to Mac OS X as “native” program. What they have done is basically build a “native” GTK+ port and then GIMP and Inkscape will not need X11 but can run in Quartz.
However, even these program run in GTK+ for Mac OS X and do not require X11 to run, they are still NOT NATIVE! What is a native Mac OS X program? A program written with Cocoa or Carbon, and even sometimes, Java could be considered native Mac OS X program. But those GTK+ programs, even with GTK+ Mac OS X port, they are still so far away from being Mac OS X program. Because they are no way integrated into the system. Their interface is a different style, and they don’t even really use Mac OS X menu.