valid GtkSpinButton widget.
Number of the pointer button for the event, usually 1, 2 or 3.
%TRUE for upwards arrow click, %FALSE for downwards arrow click.
Return: whether all actions neccessary for the button click simulation were carried out successfully.
2.14
This function will generate a @button click in the upwards or downwards spin button arrow areas, usually leading to an increase or decrease of spin button’s value.