How can I stop (or start) slippery chicken from opening score files automatically?

On OSX using SBCL, when slippery chicken writes, for example, score or MIDI files, it opens them automatically in your default PDF viewer and/or MIDI player. If you don't want this behaviour, simply place this code at the top of your Lisp file:

(set-sc-config 'cmn-display-auto-open nil) ; or T of course