Graphics

I am working on a new graphics package which uses a lot of black shapes. I am having difficulty seeing everything in Xpression Designer because the default background color for the Virtual Output is also black. Is there a way to get a virtual output of the Alpha Channel so I can confirm what is black and what is transparent? Or at the very lest, how do I change the default background color for the Virtual Output in Xpression Designer to something other than black? I feel like this is something that is hidden in the manual, but I couldn't find it.

You can't...

2 possibilities, add a background in your scene with a color like green that you will delete when your work is over...
OR
in viewport, you can visualize alpha channel (view, channel, alpha; don't have Xpression right know but I think it's this), but not in virtual output.
#XPression

You can also put a scene on layer -1 with a solid color, or import a PNG of your news anchor and place it on layer -1 to see how your graphics will look over a real image.
#XPression