Navigation tree lost


I’m still playing with XWiki but I think that I’m on the right way.
At the moment my biggest problem is that the navigation tree structure (nested pages) is lost.

I suppose that there could be a problem with an extension?!
Thank you for your support!

P.S. I would like to have the “original” structure:

Hard to tell what the problem is just by looking at the screenshots. You need to review the changes you made to your XWiki instance. Did you change the configuration on the file system? Did you modify or delete standard XWiki pages? What extensions did you install? etc. You also didn’t mention what version of XWiki you are using.

I’ve used XWiki 10.9 and upgraded to 10.10 today without solving the problem.
I can’t tell any more details. I will delete extensions to test…and will write here again.