menubar tooltip patch

[Scott Lanning]

This (minor thing) deals with tooltips display on the menubar.
Demo:
Click "File" in the menubar. Move the mouse down to select the
first menu item, and a tooltip frame appears. If you now move
the mouse right along the menu item and then move the mouse
back up to the menubar ("Buffers", say), the tooltip will
hover there blocking the menubar. You can move the mouse along
the menubar, but the tooltip still covers it up (until it times
out or you move the mouse down to select another menu item).
Patch:
Here is a patch that hides the tooltip whenever a
menu item is unselected (or selected).

--- xmenu.c-orig        Thu Jan  3 16:15:29 2002
+++ xmenu.c     Thu Jan  3 18:49:05 2002
@@ -1191,6 +1191,8 @@
   f = menubar_id_to_frame (id);
   if (f)
     {
+      Fx_hide_tip ();
+
       XSETFRAME (frame, f);
       kbd_buffer_store_help_event (frame, help);
     }

It's inside menu_highlight_callback, which is a lwlib callback.
I'm still learning emacs internals, so maybe it's no good.

For reference, (emacs-version t)
GNU Emacs 21.1.50.4 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2002-01-03 on localhost.localdomain