private
{©Drkb v.3(2007): <a href="http://www.drkb.ru" title="www.drkb.ru">www.drkb.ru</a>,
 ®Vit (Vitaly Nevzorov) - nevzorov@yahoo.com}
Procedure CMDialogKey(Var Msg: TWMKey); message CM_DIALOGKEY;
.....
procedure TForm1.CMDialogKey(var Msg: TWMKey);
begin
//здесь Ваш код
Msg.Result := 0
end;

type

 TForm1 = class(TForm)

 private

  procedure CMDialogKey( var msg: TCMDialogKey );

  message CM_DIALOGKEY;

end;

var

 Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.CMDialogKey(var msg: TCMDialogKey);

begin

 if msg.Charcode <> VK_TAB then

  inherited;

end;

procedure TForm1.FormKeyDown(Sender: TObject;

var Key: Word; Shift: TShiftState);

begin

 if Key = VK_TAB then

  Form1.Caption := 'Tab Key Down!';

end;

unit Hndltabu;

interface

uses

 SysUtils, WinTypes, WinProcs, Messages, Classes,

 Graphics, Controls, Forms, Dialogs, StdCtrls;

type

 TForm1 = class(TForm)

  Edit1: TEdit;

  Edit2: TEdit;

  Label1: TLabel;

  procedure FormCreate(Sender: TObject);

 private { Private-Deklarationen }

  procedure AppMessage(var Msg: TMsg; var Handled: Boolean);

 public { Public-Deklarationen }

 end;

var

 Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.AppMessage(var Msg: TMsg; var Handled: Boolean);

const

 shiftPressed: boolean = false;

begin

 if Msg.Message = WM_KEYDOWN then

  if not shiftPressed and (Msg.wParam = VK_SHIFT) then

  begin

  shiftPressed := true;

  Exit;

  end

  else

  begin

  if Msg.wParam = VK_TAB then

  if ActiveControl = Edit1 then

  begin

  if shiftPressed then

  Label1.Caption := 'BACKTAB!'

  else

  Label1.Caption := 'TAB!';

  Handled := true

  end

  else

  Label1.Caption := '';

  shiftPressed := false;

  end;

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

 Application.OnMessage := AppMessage;

end;

end.