In this translation of Mahabharata, it says Drupada wanted distruction of Bhishma and hence asked for son from Shiva.
king Drupada, O monarch, paid his adoration to the god Sankara for the sake of offspring, resolving in his mind to compass my destruction and practising the austerest of penances. And he begged Mahadeva, saying, 'Let a son, and not a daughter, be born unto me. I desire, O god, a son for revenging myself upon Bhishma.'
Why did Draupada wanted to end Bhishma? What was the cause of the hatred between them?