TYPO3 Core

Example:

You have:

• Page 1
  • Page 2
    • Page 4
  • Page 3

If you delete "Page 4" and end up with following tree:

• Page 1
  • Page 2
  • Page 3

Then you can't drag an element at the end of "Page 2", the only drag state that works is at the top of "Page 3". If this element was the last in a tree branch, you would not be able to append new elements at the end of it.

This happens because on opening pages with children, that tree state is persisted, but if the child page doesn't exist anymore (either deleted by myself or someone else) the invalid "expanded" state for the parent is still persisted. The tree fetches this and sets it regardless of it still being the case at the moment.