Quality/Cache - Changes quality that is automaitcally set by your connection (Red - high quality, Gray - low quality, Black - playing from cache).Queue - To delete a song from the queue, swipe from either left or right.
Select a playlist or highlight some tracks in i Tunes and then double-click on the script to execute it.
You can bring the sidebar back, sort of, but it’s not called that any more, and it doesn’t give you access to the same content as it did in the past.
When viewing any of your media libraries—accessible by clicking the icons at the top-left of the window—just click Playlists in the navigation bar at the top-center of the i Tunes window.
i Tunes 12, released with OS X Yosemite, features a new interface, which fits better with Apple’s overall desire for flatness, but changes a lot of the ways that users work with their media library.
Apple's i Tunes 12 is also controversial, since it changes many of the familiar ways we interacted with our media libraries.