Currently, there is no way to shuffle your songs directly from the Songs library. Instead, you have to create a Smart Playlist of all your songs and shuffle that. This seems unnecessarily convoluted, and also inconvenient if the playlist doesn’t auto-update when new songs are added to your library (I haven’t checked this though)
Brought benefits:
The ability to directly shuffle songs, which is clearer for users to do as opposed to having to create a Smart Playlist which isn’t immediately obvious
Screenshots / Mockup:
Envisage the same list of buttons at the top of the Songs library as is at the top of the Smart Playlist, one of these buttons being a shuffle button