There are more children than parent shows!

Code:
trace(this.parent);
trace(stageRef.getChildAt(0).parent);
trace(stageRef.numChildren);

Output:
[object Stage]
[object Stage]
1

Code is in “engine.as” and i have put “engine” as document class on “engine.fla” prop bar.
I have draged-and-dropped some flash pre-made components, like button, to the timeline.

My question: How can it show only 1 children if i check both objects for a parent and its Stage(stageRef)?