References
Libraries
Determines whether the spin button displays values outside the adjustment bounds.
See set_update_policy.
set_update_policy
When refreshing your GtkSpinButton, the value is always displayed
GtkSpinButton
When refreshing your GtkSpinButton, the value is only displayed if it is valid within the bounds of the spin button’s adjustment
SpinButtonUpdatePolicy.ALWAYS
SpinButtonUpdatePolicy.IF_VALID