Parent and child structure

Hey, I just test this parent-child structure,and here get some more details about this.
I created a page and add some container、btn、label on it. To test this structure, i did “trace info”
which just printf all addr of these obj, then I used function “lv_obj_get_child” “lv_obj_get_parent”
“lv_obj_count_children” to see how this work.
As I thought, the basic screen is the parent of page, and all those obj should be the children of page,
but it’s not, “lv_obj_count_children” tells page have only 1 child ,and all these obj point to the same parent
addr but not page, that’s weird, I can’t get obj from page. Then I found a similiar question who met with “win”, the answer is win created a container first, and all the children are created on the container, that’s teh same way paeg does. So is there any other obj share the same way?

I believe the tabview and tileview also do this.