json-editor: $ref to definitions in another file not working?

I cannot make references to external definitions to work, when running a copy of https://json-editor.github.io/json-editor/ on localhost (using python’s http.server and with AJAX switched on).

To explain, let’s say I have common.schema.json with

{
  "$schema": "http://json-schema.org/draft-04/schema",
  "definitions": {
    "known-product": {
      "title": "product",
      "type": "string",
      "enum": [ "power", "hydrogen", "heat" ]
    }
  },
  "title": "test",
  "properties": {
    "customer": { "type": "string" },
    "product": { "$ref": "#/definitions/known-product" }
  }
}

and test.schema.json with

{
  "$schema": "http://json-schema.org/draft-04/schema",
  "title": "Ref. tests",
  "properties": {
    "test-1": { "$ref": "common.schema.json#" },
    "test-2": { "$ref": "common.schema.json#/definitions/known-product" },
    "test-3": {
      "type": "object",
      "properties": {
        "Product": { "$ref": "./common.schema.json#/definitions/known-product" }
      }
    }
  }
}

Then, I put both schemas to the same folder as index.html, activate AJAX, and use test.schema.json in the editor.

In the generated editor, I would expect test-1 to ignore definitions and show customers and product, while both test-2 and test-3 should read only definitions/known-product and therefore show only the product selection. However, all three test show the same (customer and product), suggesting that that $ref ignores everything after # and simply includes the whole file. Is this a bug, a missing feature, or am I just doing it wrong?

Note: it could be related to this pull request, but it is marked as “merged” and the examples all use internal references, despite the title mentioning “nonlocal definitions”…