XL 2010 Controle Checkbox

Private Sub CheckBox1_Click()
CheckBox2.Value = Not CheckBox1.Value
ComboBox1.Enabled = True
End Sub

Private Sub CheckBox2_Click()
CheckBox1.Value = Not CheckBox2.Value
ComboBox1.Enabled = True
End Sub

Private Sub ComboBox1_Change()
Cells(1, 1) = ComboBox1
End Sub

Private Sub UserForm_Initialize()    ' Depart
Range("A1").ClearContents
ComboBox1.RowSource = ("D1:D6")
ComboBox1.Enabled = False
End Sub

Private Sub ComboBox1_Change()
    If ComboBox1.ListIndex < 0 Then Exit Sub
    If CheckBox1 Or CheckBox2 Then Cells(1, 1) = ComboBox1: Exit Sub
    MsgBox "Choisir une option !", vbExclamation, "Attention..."
    ComboBox1 = "":  ComboBox1.Set Focus  
End Sub