大家看看我下面的程序有什么问题,是关于自定义提示窗口的

可以编译通过,但执行不了,现把代码全部贴出:
unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
  TForm1 = class(TForm)
    Label1: TLabel;
    Button1: TButton;
  private
    { Private declarations }
  public
    { Public declarations }
  end;  TMyHintWindow=class(THintWindow)
  private
  FActivating:Boolean;
  FHDirection:Boolean;
  FVDirection:Boolean;
  procedure WMEraseBkgnd(var Message:
  TWmEraseBkgnd);message WM_ERASEBKGND;
  protected
  procedure paint;override;
  public
  constructor Create(AOwner:TComponent);override;
  procedure ActiveHint(Rect:TRect;const AHint:string);
  function CalcHintRect(MaxWidth:Integer;const AHint:string;AData:Pointer):TRect;override;
  end;var
  Form1: TForm1;implementation{$R *.dfm}
constructor TMyHintWindow.Create(AOwner:TComponent);
begin
   inherited Create(AOwner);
   Color:=$80FFFF;
   canvas.Font.Size:=14;
end;procedure TMyHintWindow.WMEraseBkgnd(var Message: TWmEraseBkgnd);
begin
    Message.Result:=1;
end;procedure TMyHintWindow.paint;
Var
R,ArrowR,TextR:TRect;
RectRgn,TPolyRgn,ShadowRgn:HRgn;
AP:array[0..2] of TPoint;begin
  R:=ClientRect;
  Inc(R.Left,2);
  Inc(R.Top,2);
  canvas.Font.Color:=clInfoText;
  canvas.Brush.Color:=$80FFFF;
  TextR:=R;
  ArrowR:=R;
  if Fvdirection then
  begin
     Inc(textR.Top,22);
     arrowR.Bottom:=textR.Top;
  end
  else
  begin
     arrowR.Top:=arrowR.Bottom-22;
     textR.Bottom:=arrowR.Top;
  end;
  if Fhdirection then
  begin
     if Fvdirection then
        begin
        AP[0]:=arrowr.TopLeft;
        AP[1].X:=arrowR.Left+10;
        AP[2].X:=Arrowr.Left+25;
        AP[1].Y:=arrowr.Bottom;
        AP[2].Y:=arrowr.Bottom;
        end
     else
        begin
        AP[0].X:=arrowr.Left;
        AP[0].Y:=arrowr.Bottom;
        AP[1].X:=arrowR.Left+10;
        AP[2].X:=Arrowr.Left+25;
        AP[1].Y:=arrowr.top;
        AP[2].Y:=arrowr.top;
        end;
   end
   else
   begin
      if Fvdirection then
      begin
        AP[0].X:=arrowr.Right;
        AP[0].Y:=arrowr.top;
        AP[1].X:=arrowR.Right-10;
        AP[2].X:=Arrowr.Right-25;
        AP[1].Y:=arrowr.bottom;
        AP[2].Y:=arrowr.bottom;
      end
   else
        begin
        AP[0]:=arrowr.bottomRight;
        AP[1].X:=arrowR.Right-10;
        AP[2].X:=Arrowr.Right-25;
        AP[1].Y:=arrowr.top;
        AP[2].Y:=arrowr.top;
        end;
   end;
RectRgn:=CreateRoundRectRgn(TextR.Left,textr.Top,textr.Right,textr.Bottom,10,10);
TPolyRgn:=CreatePolygonRgn(AP,3,WINDING);
CombineRgn(RectRgn,RectRgn,TPolyRgn,RGN_OR);FillRgn(canvas.Handle,RectRgn,canvas.Brush.Handle);
DeleteObject(RectRgn);
DeleteObject(TPolyRgn);DrawText(canvas.Handle,PChar(Caption),-1,TextR,DT_VCENTER OR DT_CENTER OR DT_NOPREFIX OR DT_WORDBREAK );
end;procedure TMyHintWindow.ActiveHint(Rect:TRect;const AHint:string);
beginFhdirection:=True;
Fvdirection:=True;
Factivating:=True;
try
Caption:=AHint;
Inc(Rect.Bottom,4);
UpdateboundsRect(Rect);if Rect.Left<Screen.DesktopLeft then
begin
   rect.Left:=screen.DesktopLeft;
end;
if rect.Top+Height>screen.DesktopHeight then
begin
   dec(rect.Top,Height);
   Fvdirection:=false;
end;
if rect.Left+width>screen.DesktopWidth then
begin
   dec(rect.Left,Width);
   Fhdirection:=false;
end;
if rect.Bottom<screen.DesktopTop then
begin
   rect.Bottom:=screen.DesktopTop;
   Fvdirection:=false;
end;setwindowpos(handle,HWND_TOPMOST,rect.Left,rect.Top,Width,Height,SWP_SHOWWINDOW OR SWP_NOACTIVATE);
Invalidate;
finally
Factivating:=false;
end;
end;function TMyHintWindow.CalcHintRect(MaxWidth:Integer;const AHint:string;AData:Pointer):TRect;
begin
   Result:=Rect(0,0,canvas.TextWidth(AHint) ,canvas.TextHeight(AHint));
   Inc(result.Right,22);
   inc(result.Bottom,10);
   dec(result.Top,15);   Setwindowpos(handle,HWND_TOPMOST,result.Left,result.Top,Width,Height,SWP_HIDEWINDOW OR SWP_NOACTIVATE);
   Invalidate;
end;initialization
HintWindowClass:=TMyHintWindow;