Drag and Drop между двумя компонентами ListBox

procedure TDualListDlg.DstListDragDrop(Sender, Source: TObject; X,
  Y: Integer);
var
  droppedOnIndex: integer;
  anItem: integer;
  numberOfItems: integer;
begin
  if (Sender is TListbox) and (Source is TListBox) then
  begin
    droppedOnIndex := TListBox(Sender).ItemAtPos(Point(X, Y), false);
    numberOfItems := TListBox(Source).SelCount;
    anItem := 0;
    while numberOfItems > 0 do
    begin
      if TListBox(Source).Selected[anItem] = true then
      begin
        TListBox(Sender).Items.Insert(droppedOnIndex,
          TListBox(Source).Items[anItem]);
        TListBox(Source).Items.Delete(anItem);
        TListBox(Source).Update;
        TListBox(Sender).Update;
        numberOfItems := numberOfItems - 1;
      end
      else
        anItem := anItem + 1;
    end;
  end;
end;

if (Sender is TListBox) and (Source is TListBox) then
begin
  if TListBox(Sender).Name = TListBox(Source).Name then
    Accept := False
  else
    Accept := true;
end;