How do I get rid of the “multiple describeType entries” warning?

warning: multiple describeType entries for 'selectedItem' on type 'mx.controls::ComboBox':<accessor name="selectedItem" access="readwrite" type="Object" declaredBy="mx.controls::ComboBase">  <metadata name="Bindable">    <arg key="" value="valueCommit"/>  </metadata>  ...

public static function bindProperty2(site:Object, prop:String, host:Object, chain:Object, commitOnly:Boolean = false):ChangeWatcher
{
    var cbx:ComboBox = null;
    if ( site is ComboBox ) { cbx = ComboBox(site); }
    if ( host is ComboBox ) { cbx = ComboBox(host); }
    var labelField:String = "listID";

    var w:ChangeWatcher = ChangeWatcher.watch(host, chain, null, commitOnly);

    if (w != null)
    {
    	var func:Function;

    	if ( site is ComboBox )
    	{
    		func = function(event:*):void
    		{
    			var dp:ICollectionView = ICollectionView(site.dataProvider);
    			var selItem:Object = null;

    			for ( var i:int=0; i<dp.length; i++ )
    			{
    				var obj:Object = dp[i];
    				if ( obj.hasOwnProperty(labelField) )
    				{
    					var val:String = String(obj[labelField]);
    					if ( val == w.getValue() )
    					{
    						selItem = obj;
    						break;
    					}
    				}
    			}

    			site.selectedItem = selItem;
    		};

    		w.setHandler(func);
    		func(null);
    	}
    	else
    	{
    		func = function(event:*):void
    		{
    			var value:Object = w.getValue();
    			if ( value == null )
    			{
    				site[prop] = null;
    			}
    			else
    			{
    				site[prop] = String(w.getValue()[labelField]);
    			}
    		};
    		w.setHandler(func);
    		func(null);
    	}
    }

    return w;
}