gtk/gtk.go
func (v *Container) SetFocusChild(child IWidget) {
	C.gtk_container_set_focus_child(v.native(), child.toWidget())
}
func (v *Container) SetFocusChild(child IWidget) {
	C.gtk_container_set_focus_child(v.native(), child.toWidget())
}
// SetFocusChild is a wrapper around gtk_container_set_focus_child().