How do I copy ("Assign") one CategoryPanel to another at runtime?

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, Contnrs, StdCtrls, ActnList, ButtonGroup, CategoryButtons;
 
type
  TCategoryPanel = class(ExtCtrls.TCategoryPanel)
  public
    procedure Assign(Source: TPersistent); override;
  end;
 
  TCategoryPanelGroup = class(ExtCtrls.TCategoryPanelGroup)
  protected
    function GetCategoryPanelClass: TCategoryPanelClass; override;
  end;
 
  TfrmMain = class(TForm)
    btnAddPanel: TButton;
    cpg: TCategoryPanelGroup;
    cpExisting: TCategoryPanel;
    CategoryButtons1: TCategoryButtons;
    ButtonGroup1: TButtonGroup;
    aclGroup: TActionList;
    Action1: TAction;
    Action2: TAction;
    Action3: TAction;
    Action4: TAction;
    procedure btnAddPanelClick(Sender: TObject);
    procedure Action1Execute(Sender: TObject);
  end;
 
var
  frmMain: TfrmMain;
 
implementation
 
{$R *.dfm}
 
{ TCategoryPanel }
 
procedure TCategoryPanel.Assign(Source: TPersistent);
var s: TCategoryPanel;
begin
  if Source is TCategoryPanel then
  begin
    s := TCategoryPanel(Source);
    Caption := s.Caption;
    Collapsed := s.Collapsed;
    Color := s.Color;
    CollapsedHotImageIndex := s.CollapsedHotImageIndex;
    CollapsedImageIndex := s.CollapsedImageIndex;
    // et cetera ... for properties
  end else
    inherited Assign(Source);
end;
 
{ TCategoryPanelGroup }
 
function TCategoryPanelGroup.GetCategoryPanelClass: TCategoryPanelClass;
begin
  Result := TCategoryPanel;
end;
 
{ TfrmMain }
 
procedure TfrmMain.Action1Execute(Sender: TObject);
begin
  ShowMessage(Sender.ClassName);
end;
 
procedure TfrmMain.btnAddPanelClick(Sender: TObject);
var p: TCategoryPanel;
  bg: TButtonGroup;
begin
  p := TCategoryPanel(cpg.CreatePanel(Self));
  p.Assign(cpExisting);
  // copy children
  bg := TButtonGroup.Create(Self);
  bg.Parent := p;
  bg.Align := alTop;
  bg.ButtonOptions := bg.ButtonOptions + [gboFullSize];
  bg.Assign(ButtonGroup1);;
end;
 
end.

                                              

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object frmMain: TfrmMain
  Left = 188
  Top = 81
  Caption = 'Test Category panels'
  ClientHeight = 451
  ClientWidth = 588
  Color = clBtnFace
  TransparentColorValue = clDefault
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object btnAddPanel: TButton
    Left = 294
    Top = 16
    Width = 75
    Height = 25
    Caption = 'Add Panel'
    TabOrder = 0
    OnClick = btnAddPanelClick
  end
  object cpg: TCategoryPanelGroup
    Left = 0
    Top = 0
    Width = 273
    Height = 451
    VertScrollBar.Tracking = True
    HeaderFont.Charset = DEFAULT_CHARSET
    HeaderFont.Color = clWindowText
    HeaderFont.Height = -11
    HeaderFont.Name = 'Tahoma'
    HeaderFont.Style = []
    TabOrder = 1
    ExplicitLeft = 24
    ExplicitTop = 136
    object cpExisting: TCategoryPanel
      Top = 0
      Height = 209
      Caption = 'cpExisting'
      TabOrder = 0
      object CategoryButtons1: TCategoryButtons
        Left = 0
        Top = 0
        Width = 269
        Height = 73
        Align = alTop
        ButtonFlow = cbfVertical
        Categories = <
          item
            Color = 15395839
            Collapsed = False
            Items = <
              item
              end
              item
              end
              item
              end
              item
              end>
          end
          item
            Color = 16771839
            Collapsed = False
            Items = <>
          end>
        RegularButtonColor = 14410210
        SelectedButtonColor = 12502986
        TabOrder = 0
      end
      object ButtonGroup1: TButtonGroup
        Left = 0
        Top = 73
        Width = 269
        Height = 110
        Align = alClient
        ButtonOptions = [gboFullSize, gboShowCaptions]
        Items = <
          item
            Action = Action1
          end
          item
            Action = Action2
          end
          item
            Action = Action3
          end
          item
            Action = Action4
          end>
        TabOrder = 1
        ExplicitLeft = 24
        ExplicitTop = 96
        ExplicitWidth = 100
        ExplicitHeight = 100
      end
    end
  end
  object aclGroup: TActionList
    Left = 408
    Top = 32
    object Action1: TAction
      Category = 'cpgGroup1'
      Caption = 'Test A'
      OnExecute = Action1Execute
    end
    object Action2: TAction
      Category = 'cpgGroup1'
      Caption = 'Test B'
      OnExecute = Action1Execute
    end
    object Action3: TAction
      Category = 'cpgGroup1'
      Caption = 'Test C'
      OnExecute = Action1Execute
    end
    object Action4: TAction
      Category = 'cpgGroup1'
      Caption = 'Test D'
      OnExecute = Action1Execute
    end
  end
end

                                              

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