Как это должно быть:
Попытка использовать BlendMode.ERASE:
Код приложения:
...
<s:SkinnableContainer blendMode="layer" ... skinClass="skins.TabBorder">
<mx:ViewStack ...>
<s:NavigatorContent label="Search" skinClass="skins.TabSkin" />
<s:NavigatorContent label="Customer Info" skinClass="skins.TabSkin" />
</mx:ViewStack>
<s:TabBar dataProvider="{myViewStack}" ... />
</s:SkinnableContainer>
...
skins.TabBorder:
<s:Rect left="0" right="0" top="25" bottom="0" radiusX="6" topLeftRadiusX="0">
<s:stroke>
<s:SolidColorStroke color="#ffffff" alpha="0.3" />
</s:stroke>
</s:Rect>
skins.TabBarButtunSkin:
<!-- its black rect which clears all under -->
<s:Rect blendMode="erase" top="0" left="0" right="0" bottom="-2" topLeftRadiusX="6" topRightRadiusX="6" includeIn="selectedStates, overStates">
<s:fill>
<s:SolidColor color="#000000" />
</s:fill>
</s:Rect>
Может быть, есть более простой способ?