[flexcomponents] combo box with checkbox

[luponero6767]

hi

i try to build a combobox where every item is a checkbox using
itemrender but i have a problem when the user click on a checkbox.
When the user click the combo close the dropdown list.

how can resolve this problem ???
Thx 

 <mx:ComboBox dataProvider="{ds..item}" labelField="@label"  
itemRenderer="com.itemRendererCB"  x="10" y="10" width="151"/>

-------------------------------------------------------------
in "com" directory put this file
-------------------------------------------------------------

<?xml version="1.0" encoding="utf-8"?>
<mx:HBox xmlns:mx="http://www.adobe.com/2006/mxml"; width="100%"
height="100%">

 <mx:Script>
        <![CDATA[
                
            import mx.controls.Alert;
           
                   
            private function onData(event:Event):void
            {
                this.addEventListener(MouseEvent.MOUSE_DOWN,
disablePropagation);
                
                ck.selected = false;
            
                if ( [EMAIL PROTECTED] == "true"){
                    ck.selected = true;
                }             
            }
            
             private function onChange(event:Event):void
            {
                event.stopImmediatePropagation();       
            }
             
              private function disablePropagation(event:Event):void
            {
                event.stopPropagation();       
            }
            
            
        ]]>
    </mx:Script>
    
    
        <mx:CheckBox id="ck" label="[EMAIL PROTECTED]"  
creationComplete="onData(event)"  change="onChange(event);"/>
</mx:HBox>