If you are using folder hierarchy - you can browse to a folder of singles and press the snuffle button and it will shuffle those songs.  However if you browse to folder containing subfolders, it will only play the 1st subfolder, not shuffle all of them as intented.  For example, in this screen shot - pressing the shuffle icon should randomly play those 5 subdirectories, but it only plays Ballyhoo, then jumps to a unrelated folder.  It seem this bug has been in all the recent betas, as of 799 it