Disabling the movement of a form

uses
Windows, Forms;
type
TForm1 = class(TForm)
public
procedure WMNCHitTest(var Msg: TWMNCHitTest); message WM_NCHITTEST;
end;
...
procedure TForm1.WMNCHitTest(var Msg: TWMNCHitTest);
begin
inherited;
with Msg do
if