Need a way to switch SkinnablePopUpContainer to "normal" state withouth popping up throught PopUpManager

Steps to reproduce:
1. Run the following program

<?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">

<s:Button x="10" y="10" label="Button"/>
<s:SkinnablePopUpContainer x="10" y="50" width="200" height="100">
<s:Button label="PopUp"/>
</s:SkinnablePopUpContainer>

<s:SkinnableContainer x="10" y="200" width="200" height="100">
<s:Button label="Skinnable"/>
</s:SkinnableContainer>

</s:Application>

Actual Results:
Button inside the SkinnablePopUpContainer does not display
Button in app and Button in SkinnableContainer do display.

Expected Results:
All Buttons display.

Workaround (if any):

Things are not visible since the skin is invisible in the "closed" state. Switch skin to "normal" state.