XL 2010 Sélectionner listbox selon choix Combobox

Const sep$ = " ; "

Private Sub ComboBox1_Change()
Dim i&, x$, j&
i = ComboBox1.ListIndex + 1
If i = 0 Then ComboBox1 = "": ComboBox1.DropDown: Exit Sub
x = sep & [Tableau1].Cells(i, 17) & sep
With ListBox1
    For j = 0 To ListBox1.ListCount - 1
        .Selected(j) = False 'RAZ
        If InStr(x, sep & .List(j, 0) & sep) Then .Selected(j) = True
    Next
End With
End Sub

Private Sub CommandButton1_Click()
Dim i&, j&, x$
i = ComboBox1.ListIndex + 1
If i = 0 Then Exit Sub
With ListBox1
    For j = 0 To ListBox1.ListCount - 1
        If .Selected(j) Then x = x & sep & .List(j, 0)
    Next
End With
[Tableau1].Cells(i, 17) = Mid(x, Len(sep) + 1)
Unload Me
End Sub