Disabling the close button on a Spark TitleWindow doesnt render correctly

Found in 11114

Steps to reproduce:
1. Compile and run attached MXML file.
2. Toggle the CheckBoxes to disable the TitleWindow and TitleWindow closeButton

Actual Results:
If you disable the entire TitleWindow it looks correct.
If you disable only the TitleWindow closeButton it doesnt do an alpha=0.5, but instead puts an odd rect around the close button (kind of like the over state)

Expected Results:
I think you should be able to selectively disable the close button while still keeping it visible

Workaround (if any):
Presumably i could make a custom skin and fix this myself.
One "gotcha" is that when only the close button is disabled, you'd want it to be 0.5 alpha. But if you disable the entire TitleWindow you wouldnt want the entire window to go 0.5 and the Button to go an additional 0.5 (making it like 25% alpha).

---

<?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/halo">
<s:controlBarContent>
<s:CheckBox id="chckBx2" selected="true" label="TitleWindow enabled" />
</s:controlBarContent>

<fx:Script>
<![CDATA[
protected function chckBx_changeHandler(event:Event):void

{ ttlWndw.closeButton.enabled = chckBx.selected; }

]]
>
</fx:Script>

<s:TitleWindow id="ttlWndw" title="The quick brown fox jumps over the lazy dog" width="300" height="200" enabled="

{chckBx2.selected}

" horizontalCenter="0" verticalCenter="0">
<s:controlBarContent>
<s:CheckBox id="chckBx" label="TitleWindow closeButton enabled" selected="true" change="chckBx_changeHandler(event);" />
</s:controlBarContent>
</s:TitleWindow>

</s:Application>