Delphi выдает ошибку в 16 строке (Unsatisfied forward or external declaration: 'TForm1.Label1Click')

Код:
unit Unit1;

interface

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

type
TForm1 = class(TForm)
Label1: TLabel;
Button1: TButton;
Button2: TButton;
Timer1: TTimer;
XPManifest1: TXPManifest;
procedure Label1Click(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure Timer1Timer(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1; min, sec: integer; mins, secs: string;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
min:=0;
sec:=0;
timer1.Enabled:= True;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
sec:=sec + 1;
if sec=60 then begin min:=min + 1; sec:=0; end;
if sec<10 then secs:= '0' + IntToStr(sec);
if sec>9 then secs:=IntToStr(sec);
min:=min + 1;
if min<10 then mins:= '0' + IntToStr(min);
if min>9 then mins:=IntToStr(min);
Label1.Caption:= mins+':'+secs;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
timer1.Enabled:=False; label1.Caption:='00:00';
end;

end.