Multiple bindings with TidUDPServer doesn't work?

I am trying to start an indy udpserver which listens to multiple ports. I have tried to set multiple bindings designtime and runtime, but in both cases the onudpread event only seems to fire when all possible ports have been written to by the clients. What I am trying to achieve is that the onudpread fires whenever a client writes somthing to one of the listen ports. Can anybody please shed some light on this?

In the following code sample, I press the "write to port 1000" button and the onudpread fires as expected, but when I press it the second time nothing happens. Only if I press "write to port 1001" onudpread mysteriously fires twice, once for the 1001 port write and only then the "cached" 1000 port write suddenly emerges? Is this an Indy bug, or am I missing something?


[udpserversimple.pas]

unit udpserversimple;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  IdGlobal,Dialogs, IdBaseComponent, IdComponent, IdUDPBase, IdUDPServer, IdUDPClient,
  StdCtrls,IdSocketHandle;

type
  TForm64 = class(TForm)
    IdUDPServer1: TIdUDPServer;
    IdUDPClient1: TIdUDPClient;
    Button1: TButton;
    Button2: TButton;
    procedure Button2Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure IdUDPServer1UDPRead(Sender: TObject; AData: TBytes;ABinding: TIdSocketHandle);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form64: TForm64;

implementation

{$R *.dfm}

procedure TForm64.Button1Click(Sender: TObject);
begin
  IdUDPClient1.Send('localhost',1000,'TEST');
end;

procedure TForm64.Button2Click(Sender: TObject);
begin
  IdUDPClient1.Send('localhost',1001,'TEST');
end;

procedure TForm64.FormCreate(Sender: TObject);
begin
  IdUDPServer1.Bindings.add.port := 1000;
  IdUDPServer1.Bindings.add.port := 1001;
  IdUDPServer1.Active := TRUE;
end;

procedure TForm64.IdUDPServer1UDPRead(Sender: TObject; AData: TBytes;ABinding: TIdSocketHandle);
begin
  showmessage('received on port: ' + inttostr(ABinding.port));
end;

end.


[udpserversimple.dfm]

object Form64: TForm64
  Left = 0
  Top = 0
  Caption = 'Form64'
  ClientHeight = 213
  ClientWidth = 361
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object Button1: TButton
    Left = 161
    Top = 141
    Width = 117
    Height = 25
    Caption = 'write to port 1000'
    TabOrder = 0
    OnClick = Button1Click
  end
  object Button2: TButton
    Left = 161
    Top = 180
    Width = 117
    Height = 25
    Caption = 'write to port 1001'
    TabOrder = 1
    OnClick = Button2Click
  end
  object IdUDPServer1: TIdUDPServer
    Bindings = <>
    DefaultPort = 0
    OnUDPRead = IdUDPServer1UDPRead
    Left = 123
    Top = 48
  end
  object IdUDPClient1: TIdUDPClient
    Host = '0'
    Port = 0
    Left = 133
    Top = 103
  end
end