Tag Menu active states

Hi
I refer to this discussion :
http://support.cargocollective.com/discussion/8254/tag-menu-active-states/p1

in order to create an activate state for the tag menu links, but it doesn't work for me.
I would like that when one tag link is selected in the menu, this one stay in green, the same color that the hover state.
Can you help me ?

Thanks.
Claude