Motif submenus not showing up

[Stefan Monnier]

With both the RC and the trunk code I see the following problem:

> emacs -q --no-site-file
- Click in the main window to make the splash screen disappear

- down-mouse-1 on the `Edit' menu
- move the mouse down to the `Search' submenu
- the submenu is displayed  ==> we're happy!

- move mouse outside of the menu and release the mouse button
  to get rid of the menu so we can try the second situation:

- down-mouse-1 on the `Buffers' menu
- move mouse to the `Edit' menu
- move mouse down to the `Search' submenu
- the submenu does *not* show up  ==> we're not happy!

This is on a redhat-7-ish system, with lesstif-0.93.18.


        Stefan