Remove some vestigial Combobox code. handleOnChange() will only emit a change event if the value has changed, so repeated calls aren't a problem.
Remove some vestigial Combobox code.
handleOnChange() will only emit a change event if the value has changed,
so repeated calls aren't a problem.

Perhaps it used to seem like a selectionMode=multiple Combobox value had
changed because it was a new array (but with the same values as the old array),
but that's no longer the case.

brunano21/deliteful,brunano21/deliteful