No drop shadow when systemChrome is none

As you know the Adobe Air framework enables the addition of a drop shadow to applications. I happened to get into this issue when I was trying to add a dropShadow to Posty.

The WindowedApplication Flex tag includes two intuitively named tags: dropShadowEnabled, which is boolean, and dropShadowColor which expects an hexadecimal color.
So it is simple to write something like the following code:

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<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" 
 dropShadowEnabled="true" dropShadowColor="#000" >
 
</mx:WindowedApplication>

If you run the application you’ll see the expected result: a native window with a drop shadow effect.
That’s what I did in Posty. But (… there is always a but …) at first it did not work. I spend few minutes googling around. No response. Then it came to my mind that there are strange dependencies between the properties of the WindowedApplication and the properties defined in the -app.xml file.
Few trials and errors and … gotcha! I set the systemChrome of Posty to none. But apparently there is a conflict/dependency between this property and the dropShadowEnabled tag.


Conclusion: no drop shadow effect visible when systemChrome set to none.
I don’t know whether it is a feature or a bug …