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;