Bindable Metadata does not work in SubClass

If Parent Class has defined a Bindable Metadata, it is not active in SubClass.
It was working in Flex3.

The following code demonstrates the problem. Bindable Metadata is not exist in the Sub classes.

Parent.as
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public class Parent
{

private var _value:String;

[Bindable]
public function get value():String

{ return _value; }

public function set value(value:String):void
{
if (_value != value)

{ _value = value; }

}

public function Parent()

{ super(); }
}
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Sub.as
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public class Sub extends Parent
{

override public function get value():String
{ return super.value; }

public function Sub()
{ super(); }

}
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Main.mxml
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<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
width="100%" height="100%">
<fx:Script>
<![CDATA[
import flash.utils.describeType;

import sample.Parent;
import sample.Sub;

private var parentClass:Parent = new Parent();

[Bindable]
private var subClass:Sub = new Sub();

]]>
</fx:Script>

<s:layout>
<s:VerticalLayout />
</s:layout>

<s:HGroup width="100%" height="100%">
<s:TextArea width="50%" height="100%" text="

{describeType(parentClass).toString()}

" />
<s:TextArea width="50%" height="100%" text="

{describeType(subClass).toString()}

" />
</s:HGroup>
</s:Application>
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