Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Address = "$B$2" Then
If IsError(Application.Match(Target.Value, [Liste], 0)) Then
If MsgBox("On ajoute?", vbYesNo) = vbYes Then
[Liste].End(xlDown).Offset(1, 0) = Target.Value
Sheets("Liste").[Liste].Sort key1:=Sheets("Liste").Range("A2")
Else
Application.Undo
End If
End If
End If
End Sub