AIR's spark.components.WindowedApplication would resize its contents automatically as I manually stretch window bounds or maximize/restore it. But spark.components.Window class does not provide such functionality 'out of the box': the contents of the Window don't change their size as I stretch/maximize/restore the window, when the corresponding spark.components.Window.nativeWindow instance does resize its bounds. My AIR application is required to open multiple windows, and resizable ones. How can I make them automatically resize their contents to match the nativeWindow bounds?
Assuming you mean the spark.components.Window, this is based on the skinnablecontainer so there shouldn't be anything preventing you from using a percentbased layout / constraint.
<s:Window xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
width="100%" height="100%">
Other methods for manually handling this sort of thing include listening for the ResizeEvent coming from the stage.