Private Sub Worksheet_Change(ByVal Target As Range)
Dim r As Range
Set r = Intersect(Target, Range("A2:B" & Rows.Count), Me.UsedRange)
If r Is Nothing Then Exit Sub
Application.EnableEvents = False
For Each r In r 'si entrées/effacements multiples
With r(1, 3 - r.Column) 'cellule en colonne B
If .Offset(, -1) = "" Then
.Value = ""
ElseIf Evaluate("NOT(COUNTIF(OFFSET(J2,,MATCH(A" & .Row & ",K1:N1,0),4),B" & .Row & "))") Then
.Value = "A modifier avec la liste"
End If
End With
Next
Application.EnableEvents = True
End Sub