We have no PHP support for any kind of SelectWidget, in particular no DropdownWidget (corresponds to <select> element).
- Create a new DropdownInputWidget class:
- In PHP, it's just a wrapper around a <select>
- In JS, it's a wrapper around a <input type=hidden> and a proper fun-enabled DropdownWidget
- Possibly extend this approach for MultiSelectInputWidget and such in the future…