Manipulating Combobox in Internet Explorer

I have been automating the IE browser to conduct web scraping for many years across a number of sites.

I have recently come across a combobox that will only work properly after it has been manipulated by a human.

To clarify - if I automate the selection of the dropdown using code, the combobox value changes correctly. Or rather - it APPEARS to. But then the automation clicks the download button and the file that downloads is not the option that was selected in the combobox!

But if I pause the code at this point and I change the dropdown manually in the browser before letting the code continue, the download is the option that was selected.

My question is this:

How do I alter my combobox code so that the browser actions on the combobox are the same as what would have been sent if the combobox had had its dropdown changed manually?

(Or to put it another way - how can the function be written so that its automation will mimic a humans input on a combobox)



Relevant extract below:

Option Explicit

'Requirements:
'   Reference Library =     Microsoft Internet Controls
'   DLL =                   SHDocVw (dll/COM Shell Document Viewer)

#If VBA7 And Win64 Then
    ' 64 bit Excel
    Private Declare PtrSafe Sub Sleep _
                Lib "Kernel32" ( _
                ByVal dwMilliseconds As LongLong)

#Else
    ' 32 bit Excel
    Private Declare Sub Sleep _
                Lib "Kernel32" ( _
                ByVal dwMilliseconds As Long)

#End If

Private mappIE                  As InternetExplorerMedium
Private mblnSilentFails         As Boolean

Public Function fnblnActionInputComboBox_ByITextByID(ByVal strElmtId As String, ByVal strOptionInnerText As String) As Boolean
    Dim objElement As Object
    Dim blnResult As Boolean
    Dim i As Long

    Set objElement = pfnobjSetElementById(strElmtId, mblnSilentFails)
    If objElement Is Nothing Then
        GoTo ExitProcedure
    End If

    With objElement
        If .Type <> "select-one" Then
            'Call pDebugPrintElementNotFound("Type", "select-one (but matched on Id:=" & strElmtId & ")")
            MsgBox "Element Id '" & strElmtId & " has Type '" & .Type & "' (Code was expecting 'select-one')", vbCritical
            GoTo ExitProcedure
        End If

        If LenB(strOptionInnerText) Then
            .Focus

            For i = 0 To .Options.Length - 1

                If InStr(1, .Options(i).innerText, strOptionInnerText, vbTextCompare) Then

                    strOptionInnerText = .Options(i).innerText

                    .Options(i).Focus
                    Sleep 20
                    .Options(i).Selected = True
                    Sleep 20
                    .Options(i).Click
                    Sleep 20
                    .Options(i).fireevent ("onchange")

                    .selectedIndex = i

                    Do Until .ReadyState = "complete"
                        Sleep 100
                    Loop

                    blnResult = True
                    Exit For
                End If
            Next i
        End If
    End With

ExitProcedure:
    Set objElement = Nothing
    fnblnActionInputComboBox_ByITextByID = blnResult
End Function

Private Function pfnobjSetElementById(ByVal strElmtId As String, ByVal blnBatchMode As Boolean) As Object
'/ this function is to deal with a known bug in IEs use of GetElementById
    Dim objElement As Object
    Dim strMsg As String
    Dim blnSuccess As Boolean

    On Error Resume Next
    Set objElement = mappIE.Document.GetElementById(strElmtId)
    On Error GoTo 0

    If objElement Is Nothing Then
        'If Not blnBatchMode Then
            'Call pDebugPrintElementNotFound("Id", strElmtId)
        'End If
    ElseIf objElement.ID = strElmtId Then
        blnSuccess = True
        Set pfnobjSetElementById = objElement
    Else
        With objElement
            strMsg = "Known IE bug found. Element '" & .ID & "' only matches the required Id ('" & strElmtId & "') on its Value! ('" & .Value & "')"
        End With
    End If

    If LenB(strMsg) Then
        If blnBatchMode Then
            Debug.Print strMsg
        Else
            MsgBox strMsg
        End If
    End If

ExitProcedure:

    ' scrap object
    If Not TypeName(objElement) = "Nothing" Then
        Set objElement = Nothing
    End If
End Function

I am unable to provide the website or the HTML code. In any case, I want this function to be generic enough so that I can apply it to any html combobox and it will work.