That may be a bug in the Flash CS3+ ComboBox control.
Can you please submit a bug report via http://www.adobe.com/go/wish/ and include your test code.

Thanks,
Peter

I’m not sure about Flex, I am not familiar with MXML, but in AS3 written in Flash CS3, an editable ComboBox that has been edited by the user does not respond to selectedIndex = -1 anymore;

I just opened a new Document, and threw on stage a ComboBox named cb, and a button named b, and wrote this code:

import fl.data.*;
cb.editable = true;
cb.dataProvider = new DataProvider(["one", "two", "3"]);
cb.prompt = "Choose a number";
b.addEventListener(MouseEvent.CLICK, onClickButton);
function onClickButton(e){
	cb.selectedIndex = -1;
}

Whenever you write something into the ComboBox, the button has no effect.

This seems to work for me (Flex 3.4.0.9147):

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
 
    <mx:VBox>
        <mx:ComboBox id="cb" prompt="ok" dataProvider="[One,Two,Three]" editable="true" width="100%" />
        <mx:Label text="text = {cb.text}" />
        <mx:Label text="selectedIndex = {cb.selectedIndex}" />
        <mx:Label enterFrame="event.currentTarget.text = 'prompt = ' + cb.prompt;" />
        <mx:Button label="Set selectedIndex=-1" click="cb.selectedIndex = -1;" />
        <mx:HRule width="100%" />
        <mx:Label fontWeight="bold" initialize="event.currentTarget.text = mx_internal::VERSION;" />
    </mx:VBox>
 
</mx:Application>

Peter

I’m running into a problem on resetting editable ComboBoxes back to prompt. When the user writes their own text, the ComboBox does not respond to selectedIndex=-1 anymore.

I believe if you hold down the Ctrl key (on Windows, not sure about Mac) while selecting an already selected item it will de-select that item and set the selectedIndex property back to -1.

Peter