How to Merge Two Worksheet_Change Codes

Hi,
I am trying to merge two VBA codes;

Code1:

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Column = 4 Then
Target.Offset(0, 1).ClearContents
Target.Offset(0, 2).ClearContents
Target.Offset(0, 3).ClearContents
Target.Offset(0, 4).ClearContents
Target.Offset(0, 5).ClearContents
Target.Offset(0, 6).ClearContents
Target.Offset(0, 7).ClearContents
Target.Offset(0, 8).ClearContents
Target.Offset(0, 9).ClearContents
Target.Offset(0, 10).ClearContents
Target.Offset(0, 11).ClearContents
End If
End Sub

Code2:

Private Sub Worksheet_Change(ByVal Target As Range)
Set xxx = Intersect(Target, Range("E2:O10000")) 
If Not xxx Is Nothing Then
If HasValidation(xxx) Then
Exit Sub
Else
Application.EnableEvents = False
Application.Undo
Application.EnableEvents = True
MsgBox "Your last operation was cancelled. It would have deleted data validation rules.", vbCritical
End If
End If
End Sub


Private Function HasValidation(r) As Boolean
HasValidation = True
'Returns True if every cell in Range r uses Data Validation
On Error Resume Next
For Each cll In r.Cells
x = cll.Validation.Type
If Err.Number <> 0 Then
HasValidation = False
Exit For
End If
Next cll
End Function

I have asked this other forums and someone send me below code. It works fine for 2 times but then it shows error on Application.Undo.

Private Sub Worksheet_Change(ByVal Target As Range)
    Application.EnableEvents = False
    If Target.Column = 6 Then
        Range(Target.Offset(0, 1).Address, Target.Offset(0, 11).Address).ClearContents
    End If
    Set xxx = Intersect(Target, Range("E2:F32,H2:H32"))
    If Not xxx Is Nothing Then
        If HasValidation(xxx) Then
            Application.EnableEvents = True
            Exit Sub
        Else
            Application.Undo
            MsgBox "Your last operation was cancelled. It would have deleted data validation rules.", vbCritical
        End If
    End If
    Application.EnableEvents = True
End Sub

Private Function HasValidation(r) As Boolean
    HasValidation = True
    On Error Resume Next
    For Each cll In r.Cells
        x = cll.Validation.Type
        If Err.Number <> 0 Then
            HasValidation = False
            Exit For
        End If
    Next cll
End Function

It looks like i have to change something but i couldn't find. Is there anyone to explain?

Thanks!