GtkItemFactoryEntry with the given action.
WARNING: gtk_item_factory_get_item_by_action has been deprecated since version 2.4 and should not be used in newly-written code. Use GtkUIManager instead.
gtkItemFactoryGetItemByAction(object, action)objectactioncallback.action field
of GtkItemFactoryEntryGtkWidget] the menu item which corresponds to the given action, or NULL
if no menu item was found. [ allow-none ]