[Theme: Hueman] child menu – sub child menu not appear in sidebar

Hi,
when I create a sub (child) menu, this doesn’t appear in the sidebar as a sub menu entry, but as a item of the (primary) menu.

ex.
menu 1st level it’s ok (with a circle and + to the left of the item)
– item 1
– item 2
– menu 2nd level appear in sidebar as item 1
(without the circle and + to the left)
— sub item 3 not appear in sidebar
— sub item 4 not appear in sidebar

Regards
Riccardo.