Application Subclass for...switching between application instances...

AppSwitcher.as

package
{
	import flash.events.Event;
	
	import mx.controls.SWFLoader;
	import mx.core.Application;
	import mx.managers.SystemManager;
	
	public class AppSwitcher extends Application
	{
		public var appLoader:SWFLoader;
		
		public function AppSwitcher()
		{
			super();
			
			//	Visual stuff, no preloader, removing padding, set background color...
			
			this.usePreloader = false;
			
			var style:Object =
				{ paddingTop: 0, paddingBottom: 0, paddingRight: 0, paddingLeft: 0,
					backgroundColor: "#D6D6D6", backgroundImage: "none" };
			
			for(var prop in style) setStyle(prop, style[prop]);
			
			//	Create event listener for preInit
			
			appLoader = new SWFLoader();
			appLoader.percentWidth = appLoader.percentHeight = 100;
			appLoader.visible = false;
			
			appLoader.addEventListener(Event.COMPLETE, function():void {
				//Otherwise we see an incomplete version of the SWF, before it's ready...
				SystemManager(appLoader.content).addEventListener("applicationComplete", function():void {
					appLoader.callLater(function():void { appLoader.visible = true; });
				});
			});
			
			this.addChild(appLoader);
		}
	}
}

Switcher.mxml

<?xml version="1.0" encoding="utf-8"?>
<local:AppSwitcher xmlns:mx="http://www.adobe.com/2006/mxml" xmlns:local="*" preinitialize="appInit()">
	<mx:Script>
		<![CDATA[
			public function appInit():void {
				//	Switch between applications here...
				this.appLoader.load("FileExplorer.swf");
			}
		]]>
	</mx:Script>
</local:AppSwitcher>