Recently, I have discovered (and fixed) a bug in TinyMCE, which Livefyre uses and also has the bug.
For the “getRangeAt, INDEX_SIZE_ERR” JavaScript error, have a look at my blog post.
TinyMCE JavaScript error in Opera (getRangeAt, INDEX_SIZE_ERR):
https://my.opera.com/XP1/blog/2011/07/21/tinymce-javascript-error-in-opera-getrangeat-index-size-err
See my pull request here:
https://github.com/tinymce/tinymce/pull/77/
Let me know if testing reveals that it works or doesn’t work.
This TinyMCE bug was previously reported from at least 2011-04-14, yet has not been fixed (until now, hopefully). See TinyMCE bug reports #4306 and #4372 (duplicate).
This one JavaScript error is what seems to be causing all types of problems, including the CTRL + V paste bug and the underscore bug. I fixed the bug and submitted a pull request (see above).
