Buttons in ViewNavigator.navigationContent don't size to the height of the ActionBar

Steps to reproduce:
1. Create a new Flex mobile project with this application:

<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark">

<s:ViewNavigator width="100%" height="100%">
<s:actionContent>
<s:Button label="Large Button" height="70" />
</s:actionContent>

<s:navigationContent>
<s:Button label="Menu" />
</s:navigationContent>
</s:ViewNavigator>

</s:Application>

2. Notice the height of the menu button
3.

Actual Results:

The menu button height doesn't stretch from top to bottom of the ActionBar

Expected Results:

The menu button height should stretch from top to bottom of the ActionBar

Workaround (if any):

set the height of the menu button to 70.