resizing iTunes window to fit the screen

Hi,

I know when you read the subject you thought this one was going to be stupid easy, but this might be a little more complicated. I just used migration assistant to transfer my info. and when I opened iTunes the window was bigger than I could simply could use the little thing in the bottom right corner to resize the window.

I want to make the window fit my screen properly. I also tried pushing the green button in the top left corner, and it just went to a different mode, I'm not sure what it's called, but it didn't work.

Thanks,

Brandon