Breadcrumb Demo does not trigger submit code

[woodholly]

How to reproduce:

1. open /ui/demos/basic/breadcrumb.php
2. click Afghanistan
3. click Save
   Result: Critical Error Atk4\Ui\Exception: Callback requested, but never reached. You may be missing some arguments in request URL.
   Expected result: toast with 'Form Submitted! Data saving is not possible in demo!'

Source: https://github.com/atk4/ui/blob/develop/demos/basic/breadcrumb.php

[mvorisek]

reproduced 👍

[mvorisek]

StickyGet is probably missing somewhere. PR welcomed.