VBA UserForm Frame ScrollTop function not working from class function

Question

This should be a simple task and I've been coding in VBA for 10+ years but I cannot seem to get this to work. I have a UserForm with a MultiPage (with 2 pages). I am just working on the first page (Pages(0)), which has a Frame on it. just outside the frame are dynamically added labels (A - Z) and I have made a class to handle the onclick WithEvents. When the label is clicked I want the Frame to 'ScrollTop' to the corresponding name that starts with that letter. Inside the frame is many checkboxes with users names.

Here is what the form looks like.

Here is the class event handler when the user clicked a label (Letter A - Z)

Option Explicit

Public WithEvents LetterClick   As MSForms.Label 'A - Z Letters on report output userform (to scroll the frame down to the declarant name start letter)

Dim Ctrl    As Control

Private Sub LetterClick_Click()

    With form_report_output_menu.MultiPage1.Pages(0).Frame1
    
        For Each Ctrl In .Controls
            
            If TypeName(Ctrl) = "CheckBox" Then
                Debug.Print Ctrl.Caption
                If Mid(Ctrl.Caption, 1, 1) = LetterClick.Caption Then
                    .ScrollTop = Ctrl.Top: Exit For
                End If
            End If
        Next Ctrl
    
    End With

End Sub