Sets the subtitle of the gtk.HeaderBar The title should give a user
an additional detail to help him identify the current view.
Note that GtkHeaderBar by default reserves room for the subtitle,
even if none is currently set. If this is not desired, set the
has-subtitle property to FALSE.
Sets the subtitle of the gtk.HeaderBar The title should give a user an additional detail to help him identify the current view.
Note that GtkHeaderBar by default reserves room for the subtitle, even if none is currently set. If this is not desired, set the has-subtitle property to FALSE.