Code:

unit DragMain;

interface

uses

SysUtils, WinTypes, WinProcs,  Messages,

Classes, Graphics, Controls, Forms, Dialogs, StdCrtls;

type

TForm1 = class(TForm)

   Button1: TButton;

   procedure ButtonClick(Sender: TObject);

private        

   procedure WMNCHitTest(var M: TWMNCHitTest);

                message wm_NCCHitTest;

end;

var

Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1. WMNCHitTest(var M: TWMNCHitTest);

begin

inherited;

if M.Result = htClient then

   M.Result := htCaption;

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

Close;

end;

end.