[NumLock]

Код:

unit Unit1;

interface

uses
  CommCtrl,
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, XPMan, ExtCtrls;

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    XPManifest1: TXPManifest;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
    FToolTip: HWND;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

const
  TTI_NONE = 0;
  TTI_INFO = 1;
  TTI_WARNING = 2;
  TTI_ERROR = 3;

  TTS_ALWAYSTIP = $01;
  TTS_NOPREFIX = $02;
  TTS_NOANIMATE = $10;
  TTS_NOFADE = $20;
  TTS_BALLOON = $40;
  TTS_CLOSE = $80;

  TTM_SETTITLE = WM_USER+32;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
  ti: TOOLINFO;
begin
  FToolTip:=CreateWindowEx(WS_EX_TOPMOST,
    TOOLTIPS_CLASS,
    nil,
    TTS_NOPREFIX or TTS_ALWAYSTIP or TTS_BALLOON,
    0, 0, 0, 0,
    0, 0, HInstance, nil);
  SendMessage(FToolTip, TTM_SETTITLE, 1, LPARAM(PChar('ToolTip')));
  ZeroMemory(@ti, SizeOf(TOOLINFO));
  ti.cbSize:=SizeOf(TOOLINFO);
  ti.uFlags:=TTF_SUBCLASS; 
  ti.hwnd:=Edit1.Handle;
  ti.lpszText:=PChar('Edit1');
  Windows.GetClientRect(Edit1.Handle, ti.Rect);
  SendMessage(FToolTip, TTM_ADDTOOL, 0, LPARAM(@ti));
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  DestroyWindow(FToolTip);
end;

end.