createRadialGradient when the start and end circles do not overlap

Hello public-canvas-api

I'm seeing very different createRadialGradient behavior between the 4 browsers that implement canvas today - in the scenario where the start and end circles do not overlap. See attached document for more details.

>From my reading of the spec, it seems that a 5th behavior is actually correct - see the quick mockup on the right. This is in keeping with the concept of creating a cone, using a set of concentric circles.

The code I used is:
var grad = ctx.createRadialGradient(300, 130, 100, 300, 500, 200);
grad.addColorStop(0, '#400');
grad.addColorStop(1.0, '#00f');
ctx.fillStyle = grad;
ctx.fillRect(0,0,800,800);

ctx.beginPath();
ctx.strokeStyle = "rgba(255, 0,0, 255)"; //red circle
ctx.arc(300, 130, 100, 0, Math.PI*2, true)
ctx.stroke();
  
ctx.beginPath();
ctx.strokeStyle = "rgba(0, 255,0, 255)"; //green circle
ctx.arc(300, 500, 200, 0, Math.PI*2, true)
ctx.stroke();

imho I think it would be useful to clarify this scenario in the spec (the behavior in this scenario should be defined clearly, or marked as undefined; don't depend on it) - thoughts?

Thanks
Frank Olivier
Internet Explorer Program Management