Is there an error in menu handling?

[Lennart Borgman]

I tried to play a little bit with menus. Reading the example in "(elisp) 
Menu Bar" it looked to me like I could do something like

 (defconst bw-keymap (make-sparse-keymap "Window Resizing")
   "Keymap used by `bw-window-resize-mode'.")
 (define-key bw-keymap [menu-bar bw] (cons "Resize" (make-sparse-keymap 
"Resize")))
 (define-key bw-keymap [menubar bw balance] '("Balance Windows" . 
bw-balance))

However that did not give the expected result. Indeed "Resize" was added 
to the menubar, but opening that menu item just should two items in 
bold, both saying "Resize".

Did I misread the documentation?