GuiBackgroundCtrl example?

I'm trying to set the background of a simple GUI to a solid color, independent of display resolution, and without using a large image.

It looks like a GuiBackgroundCtrl is what I should use. I'm assuming that I should be able to define a profile that has fill color and opaque attributes, specify that profile for my GuiBackgroundCtrl object, and that would work just fine.

I'm guessing that my expectations of how the object should behave (or how to use it) are incorrect, because I can't get it to render.

Does anyone have a simple example of using a GuiBackgroundCtrl that they would like to share?

Thanks.