Combobox Worksheet Selection not populating Listbox

I got the following code to populate the combobox with the worksheet names but I can't seem to get the listbox to populate with the items on the worksheet selected.

Const Root As String = "PT-"

Private Sub Cb_Submit_Click()

Dim Picked As String

' loop through Listbox2

With Me.lstSELpart
    For x = 0 To .ListCount - 1
        ' get Item# and Parts name (e.g.) from List
        If .Selected(x) = True Then
           Picked = Picked & .List(x, 0) & " " & .List(x, 1) & vbCrLf
        End If
    Next x
End With

' tell user
MsgBox "You picked:" & vbCrLf & vbCrLf & Picked & vbCrLf & "from " & Root & cmbGunSel.Text
Unload Me


End Sub


Private Sub cmbGunSel_Change()
Dim Index As Long, Col As Long, Val As Variant

' do nothing if no model was picked
If Me.cmbGunSel.Value = "" Then Exit Sub

' clear previous list
Me.lstSELpart.Clear

'do nothing if an invalid name was typed in
On Error Resume Next
If ThisWorkbook.Worksheets(Root & Me.cmbGunSel.Value).Name <> Root & Me.lstSELpart.Value Then Exit Sub

' with chosen source
With ThisWorkbook.Worksheets(Root & Me.cmbGunSel.Value)

    ' populate  second list box with checked items only
    For Each Ct In .Shapes
        If InStr(Ct.Name, "Check Box") = 1 And Ct.OLEFormat.Object.Value = 1 Then
            ' populate columns of ListBox2
            Me.lstSELpart.AddItem .Range(Ct.TopLeftCell.Address).Offset(0, 1).Text
            Index = 1
            ' loop through columns of checked item
            For Col = 2 To 4
                Val = .Range(Ct.TopLeftCell.Address).Offset(0, Col).Value
                ' format the currency column
                If Col = 4 Then Val = Format(Val, "$#,##0.00")
                Me.lstSELpart.List(Me.lstSELpart.ListCount - 1, Index) = Val
                ' increase the column index
                Index = Index + 2
            Next Col
        End If
    Next Ct
    ' set up LB2 columns
    Me.lstSELpart.ColumnCount = 4
    Me.lstSELpart.ColumnWidths = "40;200;40;40"
    
End With

End Sub


Private Sub UserForm_Initialize()

Dim ws As Worksheet, Ct As Shape

' loop through sheets and set data sources
For Each ws In ThisWorkbook.Worksheets
    ' check sheet name starts with root
    If InStr(ws.Name, Root) = 1 Then
        ' add name (less Root) to ComboBox list
        Me.cmbGunSel.AddItem Split(ws.Name, Root)(1)
    End If

Next ws

End Sub

I was given this code and all I did was change the combobox and listbox name. 

Const Root As String = "PT-"

Private Sub Cb_Submit_Click()

Dim Picked As String

' loop through Listbox2

With Me.ListBox2
    For x = 0 To .ListCount - 1
        ' get Item# and Parts name (e.g.) from List
        If .Selected(x) = True Then
           Picked = Picked & .List(x, 0) & " " & .List(x, 1) & vbCrLf
        End If
    Next x
End With

' tell user
MsgBox "You picked:" & vbCrLf & vbCrLf & Picked & vbCrLf & "from " & Root & ComboBox1.Text
Unload Me


End Sub

Private Sub ComboBox1_Change()

Dim Index As Long, Col As Long, Val As Variant

' do nothing if no model was picked
If Me.ComboBox1.Value = "" Then Exit Sub

' clear previous list
Me.ListBox2.Clear

'do nothing if an invalid name was typed in
On Error Resume Next
If ThisWorkbook.Worksheets(Root & Me.ComboBox1.Value).Name <> Root & Me.ComboBox1.Value Then Exit Sub

' with chosen source
With ThisWorkbook.Worksheets(Root & Me.ComboBox1.Value)

    ' populate  second list box with checked items only
    For Each Ct In .Shapes
        If InStr(Ct.Name, "Check Box") = 1 And Ct.OLEFormat.Object.Value = 1 Then
            ' populate columns of ListBox2
            Me.ListBox2.AddItem .Range(Ct.TopLeftCell.Address).Offset(0, 1).Text
            Index = 1
            ' loop through columns of checked item
            For Col = 2 To 4
                Val = .Range(Ct.TopLeftCell.Address).Offset(0, Col).Value
                ' format the currency column
                If Col = 4 Then Val = Format(Val, "$#,##0.00")
                Me.ListBox2.List(Me.ListBox2.ListCount - 1, Index) = Val
                ' increase the column index
                Index = Index + 1
            Next Col
        End If
    Next Ct
    ' set up LB2 columns
    Me.ListBox2.ColumnCount = 4
    Me.ListBox2.ColumnWidths = "40;200;40;40"
    
End With

End Sub

Private Sub UserForm_Initialize()

Dim ws As Worksheet, Ct As Shape

' loop through sheets and set data sources
For Each ws In ThisWorkbook.Worksheets
    ' check sheet name starts with root
    If InStr(ws.Name, Root) = 1 Then
        ' add name (less Root) to ComboBox list
        Me.ComboBox1.AddItem Split(ws.Name, Root)(1)
    End If

Next ws

End Sub

So I'm wondering am I missing something because it's conflicting with a code in my workbook.

I added the 2 files I'm working with for now. The file that I have added has the userform "frmGunParts" that I have included red and white boxes with instructions of what I want to do in my next phases. It's also the userform that I have the code in.  Thank you. Please let me know if you get the file I've been having a problem uploading files.