“For me, one of the most welcome new features of iTunes 9 was the restoration of sanity to the way that iTunes responded to the zoom button. I had long been irritated by the non-standard behavior iTunes had displayed, brazenly flaunting the accepted practice of how the zoom button worked by toggling the mini player on and off, instead of zooming the window like a well-behaved Mac app. Never once in all my years of using iTunes have I wanted to use the mini player. Whenever I tried to zoom the app and the mini player appeared, it would be quickly followed by muttering and grumbling. So you can imagine my joy and bliss at discovering that iTunes 9 finally validated what I had known all along. The zoom button was supposed to act a certain way, and if you want to do something different than the standard, then you ought to use the option/alt key.”(via TUAW)

…Until Apple backpedaled on this choice in iTunes 9.0.1, but apparently there’s a fix to get iTunes to adhere to Apples own Human Interface Guidelines. Here it is:

Open the terminal and copy this line into it:

defaults write com.apple.iTunes zoom-to-window -bool YES

Now, start or restart iTunes and feel the warm glow of a consistent UI behaviour… Oh, and you can still get the mini player. Just hold option when you click the green + button.