Not quite yet...

Added the following two overrides to my Adorner, but still nothing showing up:

    protected override int VisualChildrenCount { get { return visualChildren.Count; } }
    protected override Visual GetVisualChild(int index) { return visualChildren[index]; }

Seems if I override ArrangeOverride, finalSize is equal to {0, 0}. That's probably not good. Must be that it doesn't know how big my Adorner is supposed to be?

Why the EFF isn't this working?! I'm just getting a freakin' black canvas. I'm even trying to add an Ellipse() now to the VisualCollection, but it's not working. The override calls are being made, and the number of children is correct, just nothing seems to be showing up when the Adorner is supposed to be rendering. The example doesn't override OnRender()... so I'm guessing I shouldn't either...