Regarding "Activate a window by hovering over it with the mouse"

Hi,

Vista (or Windows 7) has a feature "Activate a window by hovering over it
with the mouse". It reminds me my Unix experience in college. But Vista's
version will activate a window when the mouse hovers over any part of the
window, rather than just over the top of the window. It makes the auto
activation so sensitive and hence causes more troubles than it helps. My
question is whether there is a way to activate a window only when mouse
hovers over the top of the window.

The whole design of this feature is to save mouse clicks. I find out that
it is causing more clicks because it's so easy to unintentionally activate
a unwanted window.

Thanks for any help.

JD