Private Sub Worksheet_SelectionChange(ByVal Target As Range)
With [B7:AP45] 'plage à adapter
.Columns(1).Interior.ColorIndex = xlNone 'RAZ
.Rows(0).Interior.ColorIndex = 15 'gris
If Not Intersect(ActiveCell, .Cells) Is Nothing Then _
Union(ActiveCell(.Row - ActiveCell.Row), ActiveCell(1, .Column - ActiveCell.Column + 1)).Interior.ColorIndex = 6 'jaune
End With
End Sub