If iSalespersonKey <> 0 Then ' are you sure "iSalespersonkey" is the name of the field or is iSalespersonskey in plural? check your DB

    Dim iIndexNum As Integer
    Dim iItemKey As Integer
    
    For iIndexNum = 0 To cboSalespersons.ListCount - 1
    
        iItemKey =Me!cboSalespersons.Column(iIndexNum, 0)
    
        If iItemKey = iSalespersonKey Then
        ' I noticed you have this as comment, you notice that already?
            'Me!cboSalespersons.ListIndex = iIndexNum
            Me!cboSalespersons.ListIndex = iIndexNum
        'try to add an event here is this condition does not apply
        else
          DoEvents  
        End If

    Next
    
End If