Custom fields and multiple values

[garbanzo]

If I add multiple values in, say, the Genre field, and separate them by a semicolon, then each different value shows up as a different entry in the Side Bar when I choose Genre from the drop down.

But if I do the same with a custom field, the entries are not separated out.

Is this by design?

I play a lot of interactive fiction, and want to keep track of the author(s) of my games. There isn't a good built-in field for this, so I need to use a custom field...

Thanks!