[flexcoders] Ok, Adobe Experts...Explain this...

[Wally Kolcz]

This goes out to any Adobe Engineers on the board...or anyone who is 
smarter than me...

Why would this snippet of code:

<s:SkinnableContainer width="100%" height="35" id="topNav" top="0" 
left="200" right="0" skinClass="skins.application.BlackBorderSkin" >
<s:layout>
<s:HorizontalLayout verticalAlign="middle" paddingLeft="5" 
paddingRight="5" />
</s:layout>
<s:Button label="Back" />
</s:SkinnableContainer>


Throw this error:
ArgumentError: Error #2004: One of the parameters is invalid.
     at flash.display::Graphics/drawRoundRect()
     at 
spark.primitives::Rect/draw()[E:\dev\4.0.0\frameworks\projects\spark\src\spark\primitives\Rect.as:459]
     at 
spark.primitives.supportClasses::StrokedElement/updateDisplayList()[E:\dev\4.0.0\frameworks\projects\spark\src\spark\primitives\supportClasses\StrokedElement.as:143]
     at 
spark.primitives.supportClasses::GraphicElement/http://www.adobe.com/2006/flex/mx/internal::doUpdateDisplayList()[E:\dev\4.0.0\frameworks\projects\spark\src\spark\primitives\supportClasses\GraphicElement.as:3828]
     at 
spark.primitives.supportClasses::GraphicElement/validateDisplayList()[E:\dev\4.0.0\frameworks\projects\spark\src\spark\primitives\supportClasses\GraphicElement.as:3812]
     at 
spark.components::Group/updateDisplayList()[E:\dev\4.0.0\frameworks\projects\spark\src\spark\components\Group.as:956]
     at 
spark.skins::SparkSkin/updateDisplayList()[E:\dev\4.0.0\frameworks\projects\spark\src\spark\skins\SparkSkin.as:191]
     at 
spark.skins.spark::ButtonSkin/updateDisplayList()[E:\dev\4.0.0\frameworks\projects\spark\src\spark\skins\spark\ButtonSkin.mxml:77]
     at 
mx.core::UIComponent/validateDisplayList()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\core\UIComponent.as:8531]
     at 
mx.managers::LayoutManager/validateDisplayList()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\managers\LayoutManager.as:663]
     at 
mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\managers\LayoutManager.as:718]
     at 
mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.0.0\frameworks\projects\framework\src\mx\managers\LayoutManager.as:1072]

Here is a hint, its the button that is the culprit. I have a theory but 
don't see any documentation or Google results that confirm...so please 
explain.

Thanks!