This is the problem: I have several types like 45rpm, vinyl, etc. When added, Muscol adds an invisible type at the beginning of the list. This causes that in the database you get something like ",5,4,3,8" instead of "5,4,3,8". Notice the comma at the beginning of the list.

I noticed this because I'm echoing the types through a list (ul, li) and using firstchild to hide the list separator on first item (see example http://tinyurl.com/pukub9r). Because of the comma, the list never seemed to hide firstchild separator and I have to go and manually remove the commas from every album I add. Any ideas?