XL 2016 ibnet

Private Sub Worksheet_Change(ByVal Target As Range)
Application.EnableEvents = False
If Target.Count > 1 Then Application.Undo: GoTo 1 'évite les entrées multiples
With [A4].CurrentRegion
    If Not Intersect(Target, .Columns(3)) Is Nothing Then
        .Columns(4).Replace Target, "", xlWhole
    ElseIf Not Intersect(Target, .Columns(4)) Is Nothing Then
        .Columns(3).Replace Target, "", xlWhole
    End If
End With
1 Application.EnableEvents = True
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
If Application.CountA(Target) = 0 Then Exit Sub 'permet les effacements multiples
Application.EnableEvents = False
If Target.Count > 1 Then Application.Undo: GoTo 1 'évite les entrées multiples
With [A4].CurrentRegion
    If Not Intersect(Target, .Columns(3)) Is Nothing Then
        .Columns(4).Replace Target, "", xlWhole
    ElseIf Not Intersect(Target, .Columns(4)) Is Nothing Then
        .Columns(3).Replace Target, "", xlWhole
    End If
End With
1 Application.EnableEvents = True
End Sub