is their a secret to button rollovers when they are linked to movies

why is it that some are very unsensative - ie you have to move your mouse over them really slowly to get them to play your movie.
on other sites there is no problem - u can move your cursor around as fast as you like and the hit state will still catch your movements, regardless of its size.

there must be a trick to this
in fact im sure their is

its just that i dont know it

can someone please explain it has been winding me up for ages.

olison