Smart Key - Calendar Mode

When pressed within a calendar-mode buffer:
  ACTION KEY
     (1) at the end of the buffer, the calendar is scrolled forward 3
         months;
     (2) to the left of any dates on a calendar line, the calendar is
         scrolled backward 3 months;
     (3) on a date, the diary entries for the date, if any, are
         displayed.
  ASSIST KEY
     (1) at the end of the buffer, the calendar is scrolled backward 3
         months;
     (2) to the left of any dates on a calendar line, the calendar is
         scrolled forward 3 months;
     (3) anywhere else, all dates with marking diary entries are marked
         in the calendar window.