menu.inc : expand/collapse only one menu

Drupal expand / collapse only one menu.
If you create 2 menu (http://site_com/admin/build/menu/menu/add) with the same(equal) elements and path:
Menu1:
Item1: (path=http://site_com/taxonomy/term/1)
-Item1-1: (path=http://site_com/taxonomy/term/2)
-Item1-2: (path=http://site_com/taxonomy/term/3)
Menu2:
Item10: (path=http://site_com/node)
-Item2: (path=http://site_com/taxonomy/term/1)
--Item2-1: (path=http://site_com/taxonomy/term/2)
--Item2-2: (path=http://site_com/taxonomy/term/3)

And go to http://site_com/taxonomy/term/2 by browser.
The work expand/collapse will be only one menu (Menu1 or Menu2).

Because the menu.inc: function menu_get_active_item(){...} returns a 1 variable rather than an array.
$mid = menu_get_active_item()

I think the two item menu should work (expand/collapse).

This needs to patch.