1. run the attached zul 2. type 'a', wait for 3 seconds, let the server updates the model
user input is cleared
user input is kept.
when the model changes, it re-renders all its DOM elements.
ZK-4537 Chosenbox clear and add selected items cause js error
ZK-4387 The popup of Chosenbox not updated after ZK-3986
ZK-4446 chosenbox problems with initially empty model