The spin button update policy determines whether the spin button displays values even if they are outside the bounds of its adjustment. See SpinButton.setUpdatePolicy.
When refreshing your gtk.SpinButton, the value is always displayed
When refreshing your gtk.SpinButton, the value is only displayed if it is valid within the bounds of the spin button's adjustment
The spin button update policy determines whether the spin button displays values even if they are outside the bounds of its adjustment. See SpinButton.setUpdatePolicy.