Inline tasks break with TinyMCE v4 (Confluence 6.14+)

Issue Summary

Creating inline tasks stopped working in Confluence v6.14.x.

My app "Diary for Confluence" makes use of the comment editor and customers really like being able to use task lists. I already spent a few hours looking into the Confluence source code but I couldn't find any extra settings that I would need to pass to the editor or something like that to enable Task Lists again. For now, it's just broken.

Steps to Reproduce

1. Open a comment editor in a page
2. Execute these commands in the console:

   AJS.Meta.set('use-inline-tasks', 'true');
   AJS.Rte.getEditor().execCommand('InsertInlineTaskList');

Expected Results

Inline Task gets inserted into the editor.

Actual Results

Nothing happens.

Notes

• Works with v6.13.x
• Fails in v6.14.x and v6.15.x
• AJS.Rte.getEditor().execCommand('InsertUnorderedList'); still works

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available.