Problem/Motivation
Install Drupal 8 (I used Simplytestme)
Create 3 terms in the tag vocabulary (or create a new vocabulary and add them there)
On the vocabulary vocubulary listing page us the drag and drop to establish a parent-child relationship among the terms
Hit save
note that from the listing page it appears that the changes didn't save
select one of the children terms and edit it,
look at it's relationships - note that even though the relationship wasn't showed on the listing page, it is here.
Proposed resolution
The problem seems to be with the way the UI is interpreting the data, since the information appears preserved
Remaining tasks
Make parent-child assignments show up on the listing page
User interface changes
Update UI on listing page to work as expected
API changes
None