My Question or Issue
The songs listed below my playlist contain songs that are already in the playlist. Not a different version of the song, but the exact same upload. If I drag the song into the playlist, the software warns that it's already added, but that doesn't happen if you use the button on the right. So there is a workaround, but this shouldn't be a problem in the first place because those songs already in the playlist shouldn't be listed at all.