Explication (trouvée depuis la doc de qdialogbuttonbox) :
"However, if there is no default button set and to preserve which button is the default button across platforms when using the QPushButton::autoDefault property, the first push button with the accept role is made the default button when the QDialogButtonBox is shown,"
[^] # explication
Posté par Octabrain . En réponse au message probleme avec PyQt4 et les signaux. Évalué à 3.
"However, if there is no default button set and to preserve which button is the default button across platforms when using the QPushButton::autoDefault property, the first push button with the accept role is made the default button when the QDialogButtonBox is shown,"
Puis :
http://doc.trolltech.com/4.5/qpushbutton.html#default-prop
"A button with this property set to true (i.e., the dialog's default button,) will automatically be pressed when the user presses enter"