Q: I am new to Mac OS X. How do I ‘fit to screen’ the iTunes window?
A: On Mac OS X, there is no “Maximize” button that automatically resizes a window to fill the entire screen. With most applications, the green button at the top-left corner of the window will resize the window to fit its content, which may or may not fill the entire screen.
In iTunes, however, this button is used to toggle between the mini-player view and the full iTunes window. To instead expand the iTunes window to fill your entire screen, hold down the Mac OPT key while clicking on the green button. OPT-clicking on the green button again will return your iTunes window to its previous size.