Code:

type

TyourForm = class(TForm)

private

   { Private declarations }

   procedure WMNCHitTest(var Message: TWMNCHitTest); message WM_NCHITTEST;

end;

procedure TyourForm.WMNCHitTest(var Message: TWMNCHitTest);

begin

inherited;

with Message do

   if Result = HTCAPTION then

     Result := HTNOWHERE;

end;