Set Panel width and height to 100% : Panel « Container « Flex
- Flex
- Container
- Panel
Set Panel width and height to 100%

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Panel layout="horizontal" width="100%" height="100%" title="this is a test"/>
</mx:Application>
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