Dig up arguments from the past
A common troll trait is to dig up arguments from the past and try to focus on them instead of the current issue. This technique is used to try to sidestep a current argument or to insult a poster when the troll feels cornered. A good example would be for the troll to claim that the opponent is ignorant because he or she couldn't do this or that, based on the earlier issue, trying to draw focus on an alledged flaw from the past to diminish the opponents credibility in this issue.
For some trolls, this also sparks an opportunity to create new Antagonizing threads based on these earlier issues.