Replication

1. Add a Comments block in the Grader's page (view.php?id=X&rownum=0&useridlistid=Y&action=grading).
2. Click on the button to rate any activity.
3. You get a JavaScript error, and the PDF viewer is not loaded:

   "container" is not defined.

   See this line in comment/comment.js:
   var container = Y.one('#comment-ctrl-'+this.client_id);

Alternative replication using LTI provider:

1. Create an assignment and publish it over LTI
2. Add a comments block to that assignment page (this will work if the assignment is accessed via the site directly)
3. Go to a consumer site, and set up a link into the published assignment using an embedded launch container
4. Observe that when you launch into the assignment, you'll see console errors.
   If you try to add a file submission to the assignment, you'll be unable to, since the file manager just spins forever.