One solution that seems to work is to pass bindEvents: false
in the .blockUI call as an option (along with message
, etc.). See http://fiddle.tinymce.com/bzeaab/17 for how the failing fiddle (at http://fiddle.tinymce.com/bzeaab/16) was amended to allow the plug in to work.
In your case, $.blockUI({ message: editDiv });
becomes
$.blockUI({ message: editDiv, bindEvents: false });
One potential downside to this issue is that this approach unbinds everything in the blockUI overlay, not just tinymce plugins, so could be too overreaching for your needs.