Barrapunto

Mejor que los propios de Qt se expliquen:
http://doc.qt.nokia.com/4.7/qtmac-as-native.html [nokia.com]

Saludos

En primer lugar, nombra Carbon. Carbon ya no existe desde, creo Snow Leopard o Lion. Las primeras versiones de QT compilaban contra Carbon porque era C y era mucho más fácil partir de ahí.

Y cito:

"Qt provides widgets that look like those described in the Human Interface Descriptions."

"Aqua feel This is a bit more subjective, but certainly Qt strives to provide the same feel as any Mac OS X application (and we consider situations where it doesn't achieve this to be bugs). "

"Aqua guides This is the most subjective, but there are many suggestions and guidelines in the Aqua style guidelines. This is the area where Qt is of least assistance. The decisions that must be made to conform (widget sizes, widget layouts with respect to other widgets, window margins, placement of OK and Cancel, etc) must be made based on the user experience demanded by your application. "

En resumen: que pese a usar Cocoa, la mitad de las cosas son emuladas.