Apparently Eve is now stricter in checking against MONGO_QUERY_BLACKLIST,
and blocks our use of $regex when getting child nodes. See
`jstree.py::jstree_get_children()`
This 'custom view' means that the URL to view the node (as returned by
url_for_node(…)) cannot be loaded via XHR and embedded in the project
viewer, but should rather be used as the actual browser URL instead.
Currently only blogs use this.
