Function CellKeyDown(row as Integer, column as Integer, key as String) As Boolean
   dim nextColumn as Integer
   if key = chr(9) then
      if keyboard.ShiftKey then
         nextColumn = column - 1
         if nextColumn < 0 then
            nextColumn = ColumnCount-1
         end if
      else
         nextColumn = column + 1
         if nextColumn >= ColumnCount then
            nextColumn = 0
         end if
      end if
      EditCell(row,nextColumn)
      return true
   end if
End Function