@:bind class that extends another @:bind class - wrong result

[CrazyFlasher]

I have a fla file with 2 assets linked to classes:

Box class:

@:bind class Box extends Sprite
{
    public var mc:MovieClip;

    public function new()
    {
        super();
    }
}

And Circle class:

@:bind class Circle extends Box
{
    public function new()
    {
        super();
    }
}

However when I instantiate Box and Circle - I see 2 boxes on the stage:

class Main extends Sprite
{
    public function new()
    {
        super();

        var box:Box = new Box();
        addChild(box);

        var circle:Circle = new Circle();
        circle.x = 200;
        addChild(circle);
    }
}

Result:

Is it a bug or known limitations that I should consider?

(Test project attached. Just run build.hxml)

inheritance_sample.zip

Best regards