SplitViewNavigator child visibility issues

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:SplitViewNavigator x="24" y="23" width="448" height="200" autoHideFirstViewNavigator="true">
<s:mxmlContent>
<s:ViewNavigator width="200" height="200" title="One">
</s:ViewNavigator>
<s:ViewNavigator width="200" height="200" title="Two">
</s:ViewNavigator>
</s:mxmlContent>
</s:SplitViewNavigator>

<s:SplitViewNavigator x="24" y="323" width="300" height="200">
<s:ViewNavigator visible="false" width="200" height="200" title="Three">
</s:ViewNavigator>
<s:ViewNavigator width="200" height="200" title="Four">
</s:ViewNavigator>
</s:SplitViewNavigator>

</s:Application>

Actual Results:
1. ViewNavigator "One" hides but does not get removed from layout when in portrait mode
2. ViewNavigator "Three" is invisible bug does not get removed from layout

Expected Results:
1. ViewNavigator "One" hides and is removed from layout when in portrait mode
2. ViewNavigator "Three" is not visible and is removed from layout

Workaround (if any):