title text renders twice with center sytle

Steps to reproduce:
1. Create a mobile project.
2. Add the some ActionBar title styles:

<?xml version="1.0" encoding="utf-8"?>
<s:MobileApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
firstView="views.mob01HomeView" title="Hello Kitty">
<fx:Declarations>
<!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>

<fx:Style>
@namespace s "library://ns.adobe.com/flex/spark";
s|ActionBar #titleDisplay

</fx:Style>
</s:MobileApplication>

Actual Results: two titles render (white and orange)

Expected Results: one title

Workaround (if any):