The traffic light controls on iTunes 10 have been flipped vertically in order to save space and make the program more streamlined, but many users don’t like this change. Luckily, there is a quick fix to put them back to where they belong.
Just type the following into the Terminal and hit enter.
defaults write com.apple.iTunes full-window -boolean YES
If you want to change it back, trade “YES” for “NO”.