Menu behaviour

This will seem a little thing, but I want to try and change the
behaviour of the XP start menu. The way I work in Vista is to click &
hold on the start button (orb) then slide up the menu until I am on the
item I want, then release the mouse button, whereupon the app launches.
With XP it seems I have to explicitly click a second time on the menu
item to launch it. As I say, just a little thing, but it's surprising
how I stumble over it when I am busy. Does anyone know of a way to get
the behaviour I like in XP please?
--
Peter in New Zealand. (Email address is fake)
Collector of old cameras, tropical fish fancier, good coffee nutter, and
compulsive computer fiddler.