Change Glow Around Dialog

How can I change the color of the glow around a dialog? I read somewhere that you can do it by making the following style,

<style name="NewBorderDialogTheme" parent="android:Theme.Dialog">
<item name="android:windowBackground">@drawable/test</item> 
&开发者_如何学Golt;/style>

But it isn't working for me, it just displays the default blue glow. Any help is appreciated. Thanks