ComboBox question2

There's no option, but you can build something. You can add a  keyboard listener to the combo box, and then add typed letters to a  search string. Then search the data provider's label property for you  search string.... Something like so should give you a start:

combo.addEventListener(Event.OPEN, comboOpened, false, 0, true);
combo.addEventListener(Event.CLOSE, comboClosed, false, 0, true);

var searchString:String;

function comboOpened(e:Event):void

{ 

     combo.addEventListener(KeyboardEvent.KEY_DOWN, searchKeyPressed, false, 0, true);

    searchString = "";

}

function comboClosed(e:Event):void

{

     combo.removeEventListener(KeyboardEvent.KEY_DOWN, searchKeyPressed);

}

function searchKeyPressed(e:KeyboardEvent):void

{

    searchString += String.fromCharCode(e.charCode); 

    for(var i:int = 0; i < combo.dataProvider.length; i++){

        if(String(combo.dataProvider.getItemAt(i).label).toLowerCase().indexOf(searchString) == 0){

            combo.selectedIndex = i;

        }

    }

}