Private Sub Worksheet_BeforeRightClick(ByVal Target As Range, Cancel As Boolean)
If Not Intersect(Range("E1:E50"), Target) Is Nothing Then
If UCase$(Target) = "OUI" Then Target.Value = "NON": Cancel = True: Exit Sub
If UCase$(Target) = "" Then Target.Value = "OUI": Cancel = True: Exit Sub
If UCase$(Target) = "NON" Then Target.ClearContents
End If
Cancel = True
End Sub