Afficher certaine colonnes seulement (Mois)

Private Sub Worksheet_Change(ByVal Target As Range)
Dim c As Range
Mois = CDate("1/" & [A2])
If Not Target.Address = "$A$2" Then Exit Sub
Application.ScreenUpdating = False
On Error Resume Next
For Each c In Rows(3).SpecialCells(xlCellTypeConstants, 2)
Select Case CDate("1/" & c)
Case Is = Mois
c.EntireColumn.Hidden = False
Case Else
c.EntireColumn.Hidden = True
End Select
Next
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
Dim c As Range, p As Range
Application.ScreenUpdating = False
Set p = Rows(3).SpecialCells(2, 2)
If [A2] = "Tout" Then
  p.EntireColumn.Hidden = False
  Else
  On Error Resume Next
  Mois = CDate("1/" & [A2])
  For Each c In p
    Select Case CDate("1/" & c)
    Case Is = Mois: c.EntireColumn.Hidden = False
    Case Else: c.EntireColumn.Hidden = True
    End Select
  Next
End If
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, Range("$A$2")) Is Nothing Then
Columns("C:IT").Hidden = True
Application.ScreenUpdating = False
Select Case Target
Case "Janv"
    Columns("C:W").Hidden = False
Case "Févr"
    Columns("X:AR").Hidden = False
Case "Mars"
    Columns("AS:BM").Hidden = False
Case "Avr"
    Columns("BN:CH").Hidden = False
Case "Mai"
    Columns("CI:DC").Hidden = False
Case "Juin"
    Columns("DD:DX").Hidden = False
Case "Juill"
    Columns("DY:ES").Hidden = False
Case "Août"
    Columns("ET:FN").Hidden = False
Case "Sept"
    Columns("FO:GI").Hidden = False
Case "Oct"
    Columns("GK:HD").Hidden = False
Case "Nov"
    Columns("HE:HY").Hidden = False
Case "Déc"
    Columns("HZ:IT").Hidden = False
 Case "Affich tout"
    Columns("C:IT").Hidden = False
End Select
End If
Application.ScreenUpdating = True
End Sub