TitleWindow component's Close button is not accessible by tabbing

Steps to reproduce:

1. Create a new project with the following component in the application tag.
<mx:TitleWindow showCloseButton="true"/>
2. Launch and try to tab to the close button.

Actual Results:
You are not able to use keyboard navigation to tab to the close button.

Expected Results:
Components like this need to be accessible for those who can only use keyboards. You should be able to get focus on the close button by default. The logic should probably be reversed. The developer not wanting to provide tab focus should be required to turn it off, not on.

Workaround (if any):
You'll have to subclass TitleWindow and override createChildren() with the following code:

override protected function createChildren():void
{
super.createChildren();

closeButton.focusEnabled = true;
titleBar.tabEnabled = true;
titleBar.tabChildren = true;
}