[Metaphor]

При нажатии на эту кнопку прога зависает

Код:

procedure TForm1.Button4Click(Sender: TObject);
begin
ListBox1.clear;
OpenedHANDLE := GetWindow(handle, gw_hwndfirst);
while OpenedHANDLE <> 0 do
begin
if (OpenedHANDLE <> Application.Handle)
and IsWindowVisible(OpenedHANDLE)
and (GetWindow(OpenedHANDLE, gw_owner) = 0)
and (GetWindowText(OpenedHANDLE, buffer, SizeOf(buffer)) <> 0)

 then
begin
GetWindowText(OpenedHANDLE, buffer, SizeOf(buffer));
ListBox1.Items.Add(StrPas(buffer));
end;
  OpenedHANDLE := GetWindow(handle, gw_hwndnext);
end;
ListBox1.ItemIndex := 0;

end;