Simple Pages heirarchy not working

I have set up my simple pages as a hierarchy with three pages coming under 'About'. This displays correctly during editing with Simple Pages when 'Hierarchy' display is chosen.

However, on the Website main page the Hierarchy I have set up is completely ignored and each and every menu entry is shown in the main list.

Can anyone help? Is this a bug or am I doing something wrong?

I have changed the theme from a left hand menu list to a top menu list and this doesn't help.

OK, so I have eventually worked out that you can create the hierarchy from 'Navigation' - which is fine - but why then is there a hierachy function within Simple Pages which is then ignored?