add:  if (this.newMailNotificationType.value != 0 && this.soundUrlLocation.value == "") this.mPreviewButton.disabled = true; else { this.mPreviewButton.disabled = false; } 
context:   systemSoundCheck: function ()  {    this.soundUrlLocation.disabled = this.newMailNotificationType.value != 1 ? true : false;  },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/5902c2eebd17d827edbb3d282edf496ad96e42ec/notifications.js/buggy/mail/components/preferences/notifications.js