position d'un commentaire sur l'écran

Option Explicit
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
With Target
    If .Column > 1 Or .Count > 1 Then Exit Sub
    If Not .Comment Is Nothing Then
        With .Comment.Shape
            .Left = (ActiveWindow.VisibleRange.Width - .Width) / 2
            .Top = ActiveWindow.VisibleRange.Top + (ActiveWindow.VisibleRange.Height - .Height) / 2
        End With
    End If
End With
End Sub

Option Explicit
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Static c As Comment
If Not c Is Nothing Then c.Visible = False
With Target
    If .Column > 1 Or .Count > 1 Then Exit Sub
    If Not .Comment Is Nothing Then
        Set c = .Comment
        With c
           .Visible = True
            With .Shape
                .Left = (ActiveWindow.VisibleRange.Width - .Width) / 2
                .Top = ActiveWindow.VisibleRange.Top + (ActiveWindow.VisibleRange.Height - .Height) / 2
            End With
        End With
    End If
End With
End Sub

Dim m
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
  If m <> "" Then Range(m).Comment.Visible = False
    If Not Target.Comment Is Nothing Then
    Target.Comment.Visible = True
    With Target.Comment.Shape
      .Left = (ActiveWindow.VisibleRange.Width - .Width) / 2
      .Top = ActiveWindow.VisibleRange.Top + (ActiveWindow.VisibleRange.Height) / 2
    End With
    m = Target.Address
  Else
   m = ""
  End If
End Sub