Menu/list ( menu ) in topframe and mouse scrolling

I've made a menu ( with an arrow next to it and the choices appear when
you click that arrow - I forgot what this is called in English )in the
topframe and the subjects open in the mainframe . But when you want to
scroll down in the mainframe you have to click in that frame first
otherwhise you'll move the menuitemschoice.
Is there a script that makes the whole thing autoclick somewhere in the
mainframe so that when you pick a menu item and you start scrolling ou
automaticly scroll the mainframe window instead of the menu ?
Thanks !
( and yes, I could probably explained this simpler )
Corien