Silverlight Transparent Background in Out-of-Browser mode

I'm sure it has been asked before (but couldn't find any resources that solves my problem), I'm creating a Silverlight application where users may install and use in OOB mode, using elevated trust. I want my "windowless window"s background to be transparent so I've set the app to run windowless in OOB mode, and put some margin around my Grid (main grid) along with a drop shadow effect. What I'm trying to achieve is the "zune window" effect: a rectangular main borderless window with drop shadow. I was able to do it in WPF but in Silverlight, I'm getting a white background:

I don't want this white backg开发者_开发技巧round, and I've double checked that NOTHING has a white background set, but I'm still getting this. How can I get rid of that white border (obviously while keeping the drop shadow effect)?

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The short answer is: you can't.

The long answer is: The Window object represents a client window with a solid color background and there is no way to change that color.