I recently deleted all of my songs from my library in order to free up some space on my computer. So, all of my songs are on the iPod. I have two different smart playlists, but I'm having trouble adding songs to them. They each already contain a good number of songs, but occassionally I see one that I would like to add. I've tried dragging it from my iPod to the smart playlist, but it did not work. What am I doing wrong? Thanks!