Standing For A Parent

In looking at Hilchos Kibbud Av V'Eim (Y.D. 240) I noticed something interesting. The Shulchan Aruch list those activities that constitute honoring and fearing a parent. However, standing for a parent is not part of the list. It is a separate halacha listed later. Why is that? Furthermore, the Shulchan Aruch paskens that one is obligated to honor his father in law. Would this include standing up for him?