Holdem split pot question
I'm a newbie at Holdem and am playing the practice tables at 888
I just saw the following scenario and realised I didn't know why the pot got split after the showdown:
Player 1 dealt KD,AD
Player 2 dealt 3H,3S
Player 1 goes all in 1336 pre-flop
Player 2 calls all in 600 pre-flop
Board is dealt 8C,5D,2C,2H,2D
So player 1 has 3 of a kind twos
And player 2 has a full house twos and threes
Yet the pot gets split with player 2 getting 1204 and player 1 getting 732
How come player 2 didn't win it all? Full house is the higher hand?
Thanks in advance for enlightenment!