Roll OVER/OUT and Drag, is it a feature or bug?

Hi guys,

Is it feature, when you finish drag operation of child element, Roll OVER/OUT will be re-dispatched to parent element?

Reproduce:

1. Use provided code
2. Start drag of a small circle until you leave green rectangle (you will see 'out' trace)
3. Now stop drag operation by releasing mouse button
4. You can see ('over' event is re-dispatched and every mouse move triggers 'out' once)

Environment:

Flash Player: 17.0.0.134, same reproducible in Chrome: 19.0.0.226

OS X El Capitan, Version 10.11.1

Example Code:

package {


    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import flash.geom.Rectangle;


    public class Main extends Sprite {
        private var _drag:Sprite;


        public function Main() {
            var sensor:Sprite = new Sprite();
            _drag = new Sprite();


            sensor.addEventListener(MouseEvent.ROLL_OUT, mouseOut);
            sensor.addEventListener(MouseEvent.ROLL_OVER, mouseOver);
            sensor.addEventListener(MouseEvent.MOUSE_DOWN, mouseDown);


            addChild(sensor);
            sensor.addChild(_drag);


            sensor.x = sensor.y = 100;
            sensor.graphics.beginFill(0x009900);
            sensor.graphics.drawRect(0, 0, 100, 100);


            _drag.graphics.beginFill(0x990099);
            _drag.graphics.drawCircle(0, 0, 5);


            _drag.x = _drag.y = 10;
        }


        private function mouseDown(e:MouseEvent):void {
            _drag.startDrag(true, new Rectangle(10, 10, 50, 0));
            stage.addEventListener(MouseEvent.MOUSE_UP, mouseUp);
        }


        private function mouseOver(e:MouseEvent):void {
            trace('over');
        }


        private function mouseOut(e:MouseEvent):void {
            trace('out');
        }


        private function mouseUp(e:MouseEvent):void {
            _drag.stopDrag();
        }
    }
}