In Excel/Access you can start typing in a combobox and then the curser will automatically jump to the first matching record (and selects this record on tab). Please add this functionality to then Combobox.
Options to add should be:
Autocomplete - true or false
AutocompleteType - first letter or Full string (displayValue)
Change selected record with arrow keys
Probably this should not Filter the items but just jump to the appropiate record.
Or a update on the current filter (which I think would be difficult to do thinking off the multiselect option which is supported)
The option should also work if isSearchable is set to false