Private Sub ComboBox1_GotFocus()
Dim a, b, e, liste$(), n&
a = Feuil2.[C3:C8]: b = Feuil3.[A2:A5] 'matrices, plus rapides
For Each e In a
If e <> "" Then
n = n + 1
ReDim Preserve liste(1 To n)
liste(n) = e
End If
Next
For Each e In b
If e <> "" Then
n = n + 1
ReDim Preserve liste(1 To n)
liste(n) = e
End If
Next
ComboBox1.List = liste
ComboBox1.DropDown 'facultatif
End Sub