Sets the subtitle of the #GtkHeaderBar. 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
#GtkHeaderBar:has-subtitle property to %FALSE.
Sets the subtitle of the #GtkHeaderBar. 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 #GtkHeaderBar:has-subtitle property to %FALSE.