In my previous post, I showed how sometimes Windows would draw native controls on top of your non-transparent windows, as pictured here:

However, I could not figure out a sure way to reproduce it. Now I have.

Here's how you do it:

1. Make a new AIR application in Flex Builder.

2. In your-app.xml, set systemChrome to none and visible to true.

3. Prevent MINIMIZE and MAXIMIZE in your WindowedApplication:

<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="init()">
    <mx:Script>
        <![CDATA[
            private function init():void
            {
             nativeWindow.addEventListener(NativeWindowDisplayStateEvent.DISPLAY_STATE_CHANGING, onDisplayStateChanging);
            }
            private function onDisplayStateChanging(event:NativeWindowDisplayStateEvent):void
            {
                if (event.afterDisplayState == NativeWindowDisplayState.MINIMIZED || event.afterDisplayState == NativeWindowDisplayState.MAXIMIZED)
                {
                    event.preventDefault();
                }
            }
        ]]>
    </mx:Script>
</mx:WindowedApplication>

4. Launch the app.

5. Click twice on the taskbar button (should do nothing).

6. Right-click on the taskbar button. Windows native system controls appear.

This is just a reliable way to make it happen every time. You don't have to do this exact thing to make them show up, they show up on their own randomly. I hope this example makes it easy for the AIR team to debug this issue.

I've exported the sample project with the above code. Click here to download.