Some people have complained about Apple’s change from icons to a menu at the top left of the iTunes window. They say that changing media libraries – Music, Movies, Podcasts, etc. – was quicker with a single click than it is choosing a menu item.
This is true, but the menu is cleaner, and less cluttered. So it’s a trade off. I don’t think people change media libraries that often, so I tend to prefer the simpler interface.
There’s a quick way to switch media libraries in iTunes 12.4. Even quicker than using the Media Picker, the new menu. Just use the keyboard. If you choose View > Media Kind, you see a sub-menu showing the various media libraries. You can switch from this menu, but not the keyboard shortcuts next to each media kind.
If you want to switch media libraries quickly, use these shortcuts. Press Command-1 for Music, Command-3 for TV Shows, Command-7 for Apps, etc. These shortcuts work when you are in your library, and also in the iTunes Store.
Unfortunately, there’s no keyboard shortcut to get from the iTunes Store back to your Music library. If you’re in the Store, pressing Command-1 to switch to Music takes you to the music section of the iTunes Store, and you still have to click My Music to get back to your library.