def start_time_f day
      #puts "start #{start_time} : #{start_time.class} #{start_time.to_date} #{day}"
      if dtstart.class == Date
        # whole day
        ""
      elsif start_time.to_date == day.to_date
        start_time.strftime('%H:%M')
      else
        "..."
      end
    end
def start_time_f day
      #puts "start #{start_time} : #{start_time.class} #{start_time.to_date} #{day}"
      if dtstart.class == Date
        # whole day
        ""
      elsif start_time.to_date == day.to_date
        start_time.strftime('%H:%M')
      else
        "..."
      end
    end
Time it starts at day, or '...'