The minimal project which will cause a bug

Main.hx

package;
import openfl.display.Sprite;
class Main extends Sprite {
	public function new () {
		super ();
		addChild(new NewClass());
	}
}

NewClass.hx

package;
import openfl.display.Shape;
import openfl.display.DisplayObjectContainer;
class NewClass extends DisplayObjectContainer { // the same bug will occur if you change parent class to `DisplayObject`
	public function new() {
		super(); // note that the contructor of `DisplayObjectContainer` is private, so does `DisplayObject`
		var a = new Shape();
		addChild(a);
		a.graphics.beginFill(0xff234567);
		a.graphics.drawCircle(0, 0, 100);
	}
}