Hi,

Here is a set of patches to have highlighting on the menu bar items (for
the non toolkit build only).

The first patch is a bit "intrusive" because it adds a menu_bar_p
selector to 'window_from_coordinates'.  Maybe it is not needed and I
could drop this selector and make 'window_from_coordinates' return
f->menu_bar_window when the mouse is on it.

The second patch is the real meat and is modeled after other
"note_*_highlight" functions.  It seems to work as expected but now I
think I need to define another face (I'm using MENU_FACE_ID now so it is
not really visual) or maybe we should be able to propertize the menu bar
entries.  WDYT?