The OpenLaszlo implementation animates four shadowed corner chevrons that interpolate between the corners of the current widget to the corners of the next widget, so they are are not as obtrusive as animating a whole rectangle (drawing a bunch of rectangles over each other tends to look cluttered, while the corner chevrons are not as visually distracting), and they work well between differently sized widgets.
The OpenLaszlo animation is a bit slower than the animation shown in this demo, and I think the slower speed of OpenLaszlo's animation works better for drawing your eye between one widget and the other.
This demo seems to move faster than eye tracking speed, and the animation appears to skip or flicker, and it go too fast to follow, especially if the widgets are far apart.