RadioButtons inside a disabled Panel can be selected via keyboard arrow keys

Steps to reproduce:
1. Compile & run:
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical">

<mx:Panel title="Choose your tee time">
<mx:RadioButton label="9:00am" groupName="timeGroup" />
<mx:RadioButton label="10:00am" groupName="timeGroup" />

<mx:Panel title="Executive Members Only" enabled="false">
<mx:RadioButton label="6:00am" groupName="timeGroup" />
<mx:RadioButton label="7:00am" groupName="timeGroup" />
</mx:Panel>

</mx:Panel>
</mx:Application>

2. Tab into the Panel
3. Use the down arrow keys to move to the disabled RadioButtons

Actual Results:
You can give focus to the disabled RadioButtons

Expected Results:
Should not be able to access the disabled RadioButtons

Workaround (if any):