Tooltip for menus is shown even when mouse pointer is not over the menu

[Lennart Borgman]

1) Start with emacs -Q.
2) Set tooltip-mode.
3) Open the "Options" menu.

A tooltip is now shown where the mouse pointer is.

Is this how it is supposed to be? Would it not be better that it was 
shown just when the mouse pointer is over the menu?

(I have tested this on w32. Is the behaviour the same on other systems?)