The Default Option

  Use the Default option from the Mark submenu to cancel a
  Work Day or Non-Work Day setting that had been explicitly
  set.  Choosing Default returns the selected day number to its
  normal font.

  Additional topics:

  *   The Work Day Option

  *   The Non-Work Day Option

  *   The Normal Day Option

  *   The Special Day Option

  *   Marking Days and Weeks

  *   Customizing General Settings