function CloneComponent(Source: TComponent;
  aInstance: TComponent = nil;
  aOwner: TComponent = nil;
  aParent: TWinControl = nil;
  Options: TCloneOptions = []): TComponent;
const
  Index: Integer = 0; // static, needs $J+ state
var
  I: Integer;
  OrgName: string;
  Stream: TMemoryStream;
begin
  Result := nil;
  if not Assigned(Source) then Exit;
  // Create new instance when needed (or just use the one given).
  if aInstance = nil then
  begin
    if aOwner = nil then
      aOwner := Source.Owner;
    Result := TComponentClass(Source.ClassType).Create(aOwner)
  end
  else
    if aInstance.ClassType = Source.ClassType then
      Result := aInstance
    else
      raise Exception.Create('<aInstance> = ' + aInstance.ClassName +
        ' is not the same component class as' +
        ' <Source> = ' + Source.ClassName);


  // Although registering of normal classes shouldn't be neccessary
  // it is required for some of the children like TToolButton, etc.
  if Source is TWinControl then
    with TWinControl(Source) do
      for I := 0 to ControlCount - 1 do
      begin
        try
          RegisterClass(TPersistentClass(Controls[I].ClassType));
        except
        end;
      end;
  try
    // Use new parent when one was given, otherwise use the one from <Source>.
    if Source is TControl then
      with TControl(Result) do
        if aParent <> nil then
          Parent := aParent
        else
          Parent := TControl(Source).Parent;


    // Clone published properties.
    OrgName := Source.Name;
    Stream := TMemoryStream.Create;
    try
      Source.Name := 'CloneComponent' + IntToStr(Index) + OrgName;
      Stream.WriteComponent(Source);
      Source.Name := OrgName;
      Stream.Position := 0;
      Result := Stream.ReadComponent(Result);
    finally
      Stream.Free;
    end;
    // Try to set caption/text when <Source> is a control
    // to the same caption/text as that of the <Source> control.
    if Source is TControl then
      if IsPublishedProp(Result, 'Caption') or
        IsPublishedProp(Result, 'Text') then
        with TControlCracker(Result) do
          if (csSetCaption in ControlStyle) and (Name = Text) then
            Text := OrgName;

  except
    // If something went wrong only free the clone
    // when it was created by this function.
    if aInstance = nil then Result.Free;
    raise;
  end;

  // Clone all Children to the new instance as well?
  if (coIncludeChildren in Options) and (Source is TWinControl) then
    with TWinControl(Source) do
      for I := 0 to ControlCount - 1 do
        if Controls[I].ClassName <> 'TToolButton' then
          CloneComponent(Controls[I], nil, nil, TWinControl(Result), Options);

  if Index < MAXINT then Inc(Index) else Index := 0;
end;