Moving page from child to sibling position doesn't check unique page name

[juergmessmer]

Use case: A page named "test" exists for a specific parent page

• if you create a page with the same name as child of another parent you're allowed to do that
• if you create a sibling with the same name you're not permitted to do that
• if you move the sub page of the sibling to the same parent page as the original "test" page, you're allowed to do this. This should not be permitted.

I tried to fix this, but I don't know how to. In PageAdminModule::moveItem() all methods used are BasePage methods and $sPosition "before", "last", "after" are not tested if the page (position) matches the unique constraint. I don't know how to implement such a constraint since parent is not easily defined? (unique = name && parent)

[juergmessmer]

with the new jquery3 and jstree update this is fixed.