sub-menu navigation bug

[Bill Richter]

In GNU Emacs 21.2.1 (i386-redhat-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2002-04-08 on porky.devel.redhat.com
configured using `configure  i386-redhat-linux --prefix=/usr --exec-prefix=/usr 
--bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share 
--includedir=/usr/include --libdir=/usr/lib --libexecdir=/usr/libexec 
--localstatedir=/var --sharedstatedir=/usr/com --mandir=/usr/share/man 
--infodir=/usr/share/info --with-gcc --with-pop --with-sound'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

I often fail to get "Spell Checking Buffer" item from the 
"Spell Checking" submenu:

emacs -q &

Click left mouse on "Tools" menu

Bring mouse down to "Spell Checking" submenu.  

I see the item "Spell Checking Buffer" on a pop-up something on the
left.  I try to select this item by taking the straight line path.  

The sub-menu quite often disappears, and sometimes the "Options" menu
replaces it.

My sysadmin figured out a work-around:  instead of taking the
straight-line path, go instead all the way left, and then up.

That means tracing a mouse-line all the way to the "Help" item, and
then travelling straight up to "Spell Checking Buffer".

That works pretty well, but sometimes I have to stay on the far left
fringe of the menu.