If you attack a player, and that player goes out of sight – heals - and someone later kills him...by going out of sight, we will obviously lose our part of the percentage in the kill, correct?
If a player is in a fight, leaves combat and heals - then gets killed by another, different player – that player will get credit. Once a pair of players leave combat with each other any damage credit is reset.
so basicly if your a rogue and like to vanish in mid combat in order to get another opener, you lose all the credit you got for the damage you did before the vanish : (