Private Sub Worksheet_Change(ByVal Target As Range)
Dim rngDV As Range
Dim oldVal As String
Dim newVal As String
Dim lUsed As Long
If Target.Count > 1 Then GoTo exitHandler
On Error Resume Next
Set rngDV = Cells.SpecialCells(xlCellTypeAllValidation)
On Error GoTo exitHandler
If rngDV Is Nothing Then GoTo exitHandler
If Intersect(Target, rngDV) Is Nothing Or Target.Row = 25 Then
'do nothing
Else
Application.EnableEvents = False
newVal = Target.Value
Application.Undo
oldVal = Target.Value
Target.Value = newVal
If Target.Column = 2 Then
If oldVal = "" Then
'do nothing
Else
If newVal = "" Then
'do nothing
Else
lUsed = InStr(1, oldVal, newVal)
If lUsed > 0 Then
If Right(oldVal, Len(newVal)) = newVal Then
Target.Value = Left(oldVal, Len(oldVal) - Len(newVal) - 2)
Else
Target.Value = Replace(oldVal, newVal & ", ", "")
End If
Else
Target.Value = oldVal _
& ", " & newVal
End If
End If
End If
End If
End If
exitHandler:
Application.EnableEvents = True
End Sub