Originally Posted by
BCRider
I'll bet you didn't run the brifters down to the lowest position before securing the cables. So when you snap the button to release cable the cable just gets loose. Otherwise there's no reason at all for the deraileurs to NOT move. Try pulling sideways on a bare cable to add tension while snapping the brifter button that releases tension. I'll bet you end up with a really saggy cable. Adjust and you should be good.
That is a possibility. BUT, according to my Campy experience you have to have the shifters at the correct resting state in order to be able to thread the cable through. You'd need some accidental shifting happening between cable threading and derailer hook up before you lost all function/movement.