WindowApplication nested in Application? Flex 4

I am making a desktop application and I am exploring different ways to use application.

When I choose to make an air app it automatically uses WindowApplication but if I want multiple windows in my application, then I need to use Application instead. I was trying to nest WindowApplication inside Application so I can have multiple windows (by Application -> new Window()) and have a chromeless, transparent program in the background. When I nest WindowApplication it works but when I click the WindowApplication (after running debug) it would throw an error: "Argument Error: Error #2025: The supplied DisplayObject must be a child of the caller".

Here is some code I used. I am using Air 2.5 with Flash Builder 4. (the xml file is default).

<?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" 
                       xmlns:mx="library://ns.adobe.com/flex/mx"
                       applicationComplete="main()">
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    <fx:Script>
        <![CDATA[
            import spark.components.Label;
            import spark.components.Window;

            private var windows:Array = new Array();

            private function main():void
            {

                var window:Window;
                var numOfWindows:Number = 2;
                for(var i:Number=0; i<numOfWindows;i++)
                {
                    window = new Window();
                    window.width = 300;                 
                    window.title = "I am Window #"+i;
                    window.height = 200;
                    window.open(true);
                    window.showStatusBar = false;   
                    windows.push(window);
                }
                trace("Complete!");
            }
        ]]>
    </fx:Script>
    <s:WindowedApplication >
    <!-- Compiles, but once I click this, it throws the error. -->
    </s:WindowedApplication>
</s:Application>

How could I have a transparent application that can control a few windows (or at least get r开发者_高级运维id of the error above)? Thanks in advance.

WindowedApplication is not intended to be used as a child element, it is a top level element. You should use Application or WindowedApplication as your root element, and never try to nest them inside each other. More information in the official language reference: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/mx/core/WindowedApplication.html