Impossible to add an existing page to a structure in tiki documentation

• Regression

It's impossible to add an existing page to a structure. Here I was trying to add the Nginx page https://doc.tiki.org/Nginx to Structure: Tiki Installation Guide / Advanced Settings

Doesn't work on https://copydoc.tiki.org/ either

Problems:

1- The procedure is super hard to find, buried in the second paragraph of (couter-intuitively) the new page section: https://doc.tiki.org/Structure-User#Adding_a_new_page

2- The officially documented procedure doesn't work
a) There is no drop target feedback when you try to move the page from the search at the bottom of https://copydoc.tiki.org/tiki-edit_structure.php?page_ref_id=3571&find_objects=nginx&search_objects=Filter&categId= to a part of the structure.
b) Mouse wheel scrolling is inhibited while scrooling, so it's impossible to reach many elements of the structure. That's a bug. If it's also a misfeature, the search area should not scrool with the structure.
c) The drop doesn't work. Nothing seems to happen no matter what part of the structure element I drop the page on.
d) Even if it did work, the save button referred to in the doc would appear off screen at the top.

3- The intuive procedure (the places a normal use would look) isn't there.
a) From the https://copydoc.tiki.org/Advanced-Settings page, I presume I am supposed to use the "Type to search ... | Add Page | [] Child" interface on the right of the structure navigation. But:
I. There is no hover help
II. If I type and select the Nginx page and click Add Page, it takes me to the edit page of the right page. But if I save the page, it's not added to the structure.
III. The "Child" Button has no effect on the above. Even if it were a new page, I don'T understand what it's for. I am already on a a structure page, where else than as a child would I want to add the page (new or existing). But maybe it's for something else, once again there is now hover help.
b) From the page itself https://copydoc.tiki.org/Nginx
I. For a site using structure, if I have access to edit the pages I would expect an interface to add the page to a structure for a site using structures. But I guess some people may only want structures on part of the site.
II. From the edit interface (https://copydoc.tiki.org/tiki-editpage.php?page=Nginx), I have a Categories tab. I would expect a similar "Structures" tab. Failing that The interface clearly implies that clicking on Properties / Structures would allow me to place it, but it does not pre-fill the page in search (It should at the very least point to https://copydoc.tiki.org/tiki-edit_structure.php?page_ref_id=3571&find_objects=nginx&search_objects=Filter) , and it should work (so back to problem 2)

This bug has been demonstrated on show2.tiki.org

Please demonstrate your bug on show2.tiki.org

This bug has been demonstrated on show.tikiwiki.org

Please demonstrate your bug on show.tikiwiki.org