2nd level submenus?

[Marsu42]

I tried to add a 2nd level submenu to the sticky modes feature, but it didn't work - see near sticky_modes_display_values in https://bitbucket.org/hudson/magic-lantern/pull-request/72/sticky-modes-new-bracketing-sequence-delay/diff)

Did I do something wrong (certainly possible my these manual menu structures) or are 2nd level submenus simply not supported currently? Is there any other place in the menu structure where 2nd level submenus already exist so I have a template to copy/paste?