Normally you can get the position of any element by TransformToVisual. This is how you get the top left (0,0) point of the DragCue, relative to the root element:
|var transform = (e.Options.DragCue as FrameworkElement).TransformToVisual(null);
|var topLeft = transform.Transform(new Point(0, 0));
This code will throw an exception in the current release (this actually is a bug in the Popup). We have fixed this is the Q3 release of the controls (which will be available this week).
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