It gets better. In my Spanish campaign, I used one of the many princesses I got in that game to steal a French general away. He didn't wind up in my family tree, like happened to the original poster in this thread. SOMEHOW, the game selected him as the faction heir when my king died and the prince became king, still not showing up in the family tree. When that king died and the (formerly French) prince became king, my entire family tree vanished completely! The only thing showing were the greyed out portraits of the original king and queen from the beginning of the game.