Comment 2 for bug 977803

That seems a regression from the recent changes (Ken backported those to distro):

libdbusmenu (0.5.99-0ubuntu2) precise; urgency=low

  * libdbusmenu-glib/server.c
    - Cherry picked a fix for a regression in about-to-show grouping
  * libdbusmenu-gtk/genericmenuitem.c
    - Fixed: underscore on menu items change on switching focus (LP: #903200)
  * libdbusmenu-gtk/parser.c
    - Fixed: nautilus crashed with SIGSEGV in
      dbusmenu_menuitem_property_remove() (LP: #959821)