flashbackzoo / ss4-treedropdownfield-baseid-bug

https://github.com/silverstripe/silverstripe-admin/issues/954

SilverStripe TreeDropdownField Bug

silverstripe/silverstripe-admin#954

TreeDropdownField fails to load items when TreeBaseID is set.

Setup

1. vagrant up
2. vagrant ssh
3. sudo php-switch 7.1
4. composer install
5. sspak load testcase.sspak

Steps to reproduce the issue

1. Login to the CMS with admin / admin
2. Navigate to the "Example" model admin
3. Edit the "My Example" item
4. Expand the "Place" dropdown
5. Show the child items for "Te Aro" by clicking the right arrow button

Expected behaviour

Child items are loaded.

Actual behaviour

Child items fail to load and no options are selectable.