Hmmmmmmm. The select I was testing with is one of four, and the other three work fine (use the same event handler). Also after using one of the other selects this one starts working as well.
EDIT: NVM, it's not the other selectboxes that make it work, it's my inputfield that has a different event handler. I'm going to look around some more and maybe post here if I still can't find it.
It seems to have something to do with the plugin I'm using for my dropdowns. I'm going to try and figure out what the problem is but it must be conflicting somewhere because when I turn that plugin off it works like a charm.