func (v *ListBox) SetPlaceholder(placeholder IWidget) {
	C.gtk_list_box_set_placeholder(v.native(), placeholder.toWidget())
}
func (v *ListBox) SetPlaceholder(placeholder IWidget) {
	C.gtk_list_box_set_placeholder(v.native(), placeholder.toWidget())
}
// SetPlaceholder is a wrapper around gtk_list_box_set_placeholder().