I can't get this dependent multiple combo box menu to work.........

[IziJp]

I want to use this combobox menu dependently to access 10 different category menu with its sub-category, item, sub-item etc.
The vab code isn't displaying the menus with ID 10, 100, 101 etc, please how do I fix this? I have been on it for a week now, but no luck.
PLEASE HELP!!!

Option Explicit

Dim id_line As Integer           ' 加工ライン名のシート
Dim id_section As Integer        ' メンテナス項目のシート
Dim id_koukan As Integer         '交換ヶ所のシート
Dim id_subsection1 As Integer    '交換部品その①のシート
Dim id_subsection2 As Integer    '交換部品その②のシート


Private Sub cbo_Kakoumei_Change()
Dim a As Integer
Dim b As Integer

cbo_Section.Clear

With Sheet2 ' メンテナス項目のシート
        
        id_line = cbo_Kakoumei.ListIndex + 1
        
    b = .Cells(1, 1).End(xlDown).Row

    For a = 2 To b
        If Mid(.Cells(a, 1), 1, 1) = id_line Then
            cbo_Section.AddItem (.Cells(a, 2))
        End If
    Next

End With

End Sub

Private Sub cbo_Section_Change()
Dim a As Integer
Dim b As Integer

cbo_KoukanKasho.Clear

With Sheet3 ' 交換ヶ所のシート
        
        id_section = cbo_Section.ListIndex + 1
        
    b = .Cells(1, 1).End(xlDown).Row

    For a = 2 To b
        If Mid(.Cells(a, 1), 1, 1) = id_line And _
           Mid(.Cells(a, 1), 2, 1) = id_section Then
          
            cbo_KoukanKasho.AddItem (.Cells(a, 2))
            
        End If
    Next

End With

End Sub

Private Sub cbo_KoukanKasho_Change()
Dim a As Integer
Dim b As Integer

cbo_Koukanbuhin1.Clear

With Sheet4 '交換部品その①のシート

        id_koukan = cbo_KoukanKasho.ListIndex + 2
        

    b = .Cells(1, 1).End(xlDown).Row

    For a = 2 To b
        If Mid(.Cells(a, 1), 1, 1) = id_line And _
           Mid(.Cells(a, 1), 2, 1) = id_section And _
           Mid(.Cells(a, 1), 3, 1) = id_koukan Then
          
            cbo_Koukanbuhin1.AddItem (.Cells(a, 2))
            
        End If
    Next

End With
End Sub

Private Sub cbo_Koukanbuhin1_Change()
Dim a As Integer
Dim b As Integer

cbo_Koukanbuhin2.Clear

With Sheet5 '交換部品その②のシート

        id_subsection1 = cbo_Koukanbuhin1.ListIndex + 2
        

    b = .Cells(1, 1).End(xlDown).Row

    For a = 2 To b
        If Mid(.Cells(a, 1), 1, 1) = id_line And _
           Mid(.Cells(a, 1), 2, 1) = id_section And _
           Mid(.Cells(a, 1), 3, 1) = id_koukan And _
           Mid(.Cells(a, 1), 4, 1) = id_subsection1 Then
            
           cbo_Koukanbuhin2.AddItem (.Cells(a, 2))
          
        End If
    Next

End With
End Sub

Private Sub cbo_Koukanbuhin2_Change()
Dim a As Integer
Dim b As Integer

With Sheet5 '交換部品その②のシート

        id_subsection2 = cbo_Koukanbuhin2.ListIndex + 2
        

    b = .Cells(1, 1).End(xlDown).Row

    For a = 2 To b
        If Mid(.Cells(a, 1), 1, 1) = id_line And _
           Mid(.Cells(a, 1), 2, 1) = id_section And _
           Mid(.Cells(a, 1), 3, 1) = id_koukan And _
           Mid(.Cells(a, 1), 4, 1) = id_subsection1 And _
           Mid(.Cells(a, 1), 5, 1) = id_subsection2 Then

            
        End If
    Next

End With
End Sub


Private Sub UserForm_Initialize()
Dim a As Integer
Dim b As Integer

With Sheet1 '加工ライン名

b = .Cells(1, 1).End(xlDown).Row

    For a = 2 To b
        If .Cells(a, 1) <> "" Then
            cbo_Kakoumei.AddItem (.Cells(a, 2))
        End If
    Next

End With
End Sub