Private Sub Worksheet_Change(ByVal Target As Range)
On Error Resume Next
Application.ScreenUpdating = False
Application.EnableEvents = False
For Each cell In Target
   If Not Intersect(cell, Range("O2:O200")) Is Nothing Then
        With cell.Offset(0, -14)
           .Value = Now
           .EntireColumn.AutoFit
        End With
   End If
Next cell
Application.EnableEvents = True
Application.ScreenUpdating = True
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
     
    For Each cell In Target
       If Not Intersect(cell, Range("O2:O200")) Is Nothing Then
            With cell.Offset(0, -14)
               .Value = Now
               .EntireColumn.AutoFit
            End With
       End If
    Next cell
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Dim n As Integer
    If Target.Count > 1 Then Exit Sub
    On Error Resume Next
    n = Target.Validation.Type
    If n = 3 Then Application.SendKeys "%{DOWN}"
    On Error GoTo 0
End Sub