showing child category menus when selected the parent category

Hi Everyone,

I am not sure if this has been answer. I would like to know if it is possible to display the child category menus only when you are on the selected parent menu. For example, if I have a Category menu bar with food, drinks, places. I only want to show the parent menu bar on the home page, but when selecting food I want the child menu bar for food displaied. Is this something that can be done with ATO?

thanks in advance.
Mll