There is nothing to activate to make the parent link work, I think its a js problem. 

admin>themes and layout>member options>??

I am sorry I do not understand, is it in the theme setting?

Hello, I have your Greeny theme and it works perfect for my application, the problem I am having is the Main menu parent link does not work if there are sub menu's. For example the Gallery link when clicked on will drop the sub menus but the Gallery link will not work so users have to find another avenue to get to the Gallery. Its very annoying and help on this would be appreciated.