Files shows up several times when Genre selected

Why do songs (there are no duplicate files, just check the filename column) show up multiple times?
Sometimes each song show up two times, sometimes 3 times..

This happens when I select a particular Genre (I've gone trough all the ide3 tags manually, and there should be no problems with them causing this.. selecting either of the duplicate entries in the Genre list shows the same list of songs)

There are no duplicates shown in the song list when I select "all" genres, or a specific Artist/Album