Logic Pro 9 Probably the dumbest question (help a newbie)

Hi Folks,

I'm a newbie to Logic - I bought Logic Studio last month, and I have used Garage Band a lot.

Anyway, I'm sure this is something that I'm overlooking, but, when I open a new composition, i am able to preview/hear loops in the loop browser, but I don't hear anything when I move a loop into the arrange window. Anyone have any ideas? There doesn't seem to be any problems previewing the loops, this problem only occurs in the arrange window.
Green loops also should get converted automatically to audio if you drag them to an audio track. At least that's what happens here. (Or am I misunderstanding something?)