I may be misunderstanding the documentation, but the following has been cut and pasted directly from the QPushButton class reference notes:

"A push button emits the signal clicked() when it is activated by the mouse, the Spacebar or by a keyboard shortcut. Connect to this signal to perform the button's action. Push buttons also provide less commonly used signals, for example, pressed() and released().

Command buttons in dialogs are by default auto-default buttons, i.e. they become the default push button automatically when they receive the keyboard input focus. A default button is a push button that is activated when the user presses the Enter or Return key in a dialog. You can change this with setAutoDefault(). Note that auto-default buttons reserve a little extra space which is necessary to draw a default-button indicator. If you do not want this space around your buttons, call setAutoDefault(false).

Being so central, the button widget has grown to accommodate a great many variations in the past decade. The Microsoft style guide now shows about ten different states of Windows push buttons and the text implies that there are dozens more when all the combinations of features are taken into consideration.

The most important modes or states are:

* Available or not (grayed out, disabled).
* Standard push button, toggling push button or menu button.
* On or off (only for toggling push buttons).
* Default or normal. The default button in a dialog can generally be "clicked" using the Enter or Return key.
* Auto-repeat or not.
* Pressed down or not."

This seems to indicate that my advice is correct.