change event listener not notified when last value removed

[johnkary]

1. Add to a form panel and configure with a listener for "change" event.
2. Select 2 or more values from the drop-down so 2 labels appear in the box.
3. Remove one value by clicking the X in its label. A "change" listener is notified.
4. Remove last value by clicking the X. The "change" listener is NOT notified.