gtkScrolledWindowSetPolicy(object, hscrollbar.policy, vscrollbar.policy)objecthscrollbar.policyvscrollbar.policyGtkPolicyType enumeration. If GTK_POLICY_ALWAYS, the
scrollbar is always present; if GTK_POLICY_NEVER, the scrollbar is
never present; if GTK_POLICY_AUTOMATIC, the scrollbar is present only
if needed (that is, if the slider part of the bar would be smaller
than the trough - the display is larger than the page size).