Editable area in menu : nav or class "active" mandatory, not ul/li?

Hello,
I would like use an editable area on my second menu (named ssmenu) which is a component (cf image) for highlight the choice menu but when I update the project, the class modified (value “selection”) disappear on my page (Rapport.html) which use the master page (MesConseils.html) and use the menu component “ssmenu”. Maintain the class is ok only with nav, not with ul/li or i have forget something or it is a bug ?
Thanks for any help.
Brigitte