Menu creation in Explorer

Hello,

I'd like to a submenu to the Menu Setup in Explorer.
I usually use this kind of code to do it.

(deRegUserTriggers "explorer" nil nil 'customMenusInExplorer)

(defun customMenusInExplorer (largs)
(let (wid session s_setupMenu submenu1)
(setq wid (getq largs window))
(setq session (getq wid sevSession))
(setq s_setupMenu
   (car (setof x (hiGetBannerMenus wid) (pcreMatchp "Set[&]?up" (getq (eval x) _menuTitle)))))
(setq submenu1
   (hiCreatePulldownMenu 'submenu1
                                          "submenu1"
                                          (list (hiCreateMenuItem ?name 'subsubmenu1
                                                                                ?itemText "subsubmenu1"
                                                                                ?callback (sprintf nil "(CBsubsubmenu1 '%L)" ,session))
                                                 (hiCreateMenuItem ?name 'subsubmenu2
                                                                                 ?itemText "subsubmenu2"
                                                                                 ?callback (sprintf nil "(CBsubsubmenu2'%L)" ,session)))))
(hiAddMenuItem (symeval s_setupMenu) (hiCreateSliderMenuItem ?name 'sliderCustomMenu ?itemText "Custom Menu" ?subMenu submenu1))
) ; let
) ; defun

I've bee told that getting the session like I do may be source of trouble (several Explorer opened,...)

Do you confirm? If so, is there a safer way to do it?

Laurent.