incrémenter une valeur dans une cellule

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
ListBox1.Visible = False
End Sub

Private Sub Worksheet_BeforeRightClick(ByVal Target As Range, Cancel As Boolean)
With ActiveCell
  If .Row = 1 Or .Column < 8 Or Cells(.Row, 1) = "" Or Cells(1, .Column) = "" Then Exit Sub
  Cancel = True
  ListBox1.Top = .Top
  ListBox1.Left = .Offset(, 1).Left
End With
ListBox1.ListIndex = -1
ListBox1.Visible = True
End Sub

Private Sub ListBox1_Change()
Dim montant#, L%
montant = 2 'modifiable
L = ListBox1.ListIndex
If L = -1 Then Exit Sub
ActiveCell = ActiveCell + IIf(L = 0, montant, IIf(L = 1, -montant, 0))
If ActiveCell < montant Then ActiveCell = ""
ListBox1.Visible = False
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
ListBox1.Visible = False
End Sub

Private Sub Worksheet_BeforeRightClick(ByVal Target As Range, Cancel As Boolean)
With ActiveCell
  If .Row = 1 Or .Column < 8 Or Cells(.Row, 1) = "" Or Cells(1, .Column) = "" Then Exit Sub
End With
Cancel = True
Afficher
End Sub

Private Sub ListBox1_Change()
Dim montant#, L%
montant = 2 'modifiable
L = ListBox1.ListIndex
If L = -1 Then Exit Sub
ActiveCell = ActiveCell + IIf(L = 0, montant, IIf(L = 1, -montant, 0))
If ActiveCell < montant Then ActiveCell = ""
If L = 2 Then ListBox1.Visible = False: ActiveCell.Activate Else Application.OnTime 1, Me.CodeName & ".Afficher"
End Sub

Private Sub Afficher()
With ListBox1
  .Top = ActiveCell.Top
  .Left = ActiveCell(1, 2).Left
  .ListIndex = -1
  .Visible = True
End With
End Sub