using a smaller window?

hey guys, I've just bought fm11 and using a mac. I was just wondering if anyone could help me make the window in which the game is shown smaller so i can do other things on my computer whilst playing the game. At the moment, when i go into the game, i cant manouvre around my computer unless i exit the game. Thanks guys.

Go to Prefrences/Display and Sound/Display mode and choose windowed.