Strange ComboBox Bug

[Zakary]

I'm Every one

I've create a function That help me fill my combobox's, like this:

Public Sub FillComboBox(ByVal pCombo As System.Windows.Forms.ComboBox, ByVal pAccesBD As clsAccesDBSQL, ByVal pSQLQuery As String)
 
        Dim dt As DataTable
        dt = pAccesBD.GetDataSet(pSQLQuery).Tables(0)
        pCombo.DataSource = dt
 
        If dt.Rows.Count > 0 Then
 
            pCombo.BeginUpdate()
 
            pCombo.ValueMember = dt.Columns(0).ToString
            pCombo.DisplayMember = dt.Columns(1).ToString
 
            pCombo.EndUpdate()
 
        End If
 
        pCombo.SelectedIndex = -1
    End Sub

My filled ComboBox, is on a TabControl on a Form, and when I switch to the second Tab and come back to the first tab, the First Item in my ComboBox is selected !?!? , I've absolutly no code "behind" that do so, and if I look to the SelectedIndex Before the tab switf it equal -1 after it's equal to 0

Do somebody can help ...