Comment enlever les blancs dans ComboBox

Private Sub UserForm_Initialize()
    Dim liste As Object
    Dim first_cell As Range, last_cell As Range
    
    Set liste = CreateObject("System.Collections.Arraylist")
    With Sheets("Stock")
        Set first_cell = .Range("A2")
        Set last_cell = .Columns("A").Find("*", SearchDirection:=xlPrevious)
    End With
    For Each cell In Range(first_cell, last_cell)
        If cell <> Empty _
        And Not liste.contains(cell.Value) Then liste.Add cell.Value
    Next cell
    
    liste.Sort
    If liste.Count > 0 Then Me.mat.List = liste.toarray
    
End Sub