Are siblings and children the same?

Hi you guys,
I am trying to use the siblings-panel to show pages what I assume are siblings, meaning on the same level as the active page.
For example:
I have a structure as following

  1. Page
    1.1) Page
    1.2) Page
    1.3) Page

The pages 1.1), 1.2) and 1.3) are one level underneath the 1) page and xwiki displays them as such in the navigation structure. So those pages should be children to the 1) page but siblings to each other, right?
So if I use the siblings panel on those pages I want 1.2) and 1.3) to show up in the panel when I open the 1.1) page and so on…

My problem is that the children panel and the sibling panel show the same exact pages. Meaning, in both panels the children are listed. (Or what I understand to be children)
Page 1) shows 1.1), 1.2) and 1.3) as children (which is correct) and 1.1), 1.2) and 1.3) as siblings (which is not correct)
Page 1.1) shows no results as children (which is correct) and no results as siblings (which I don’t understand)
Same with pages 1.2) and 1.3)

Does anyone have the same problem or am I misundertsanding something here?
Is there another way to display pages that are on the same level?
Help would be greatly apprechiated.

Best wishes,
San