Solved K 3.0.2 message preview not working

I don't know if it can help but I'm trying to debug with IE 10 Developer Tool.
When I start to write the post I trigger the event (onChangeing or something similar I suppose) but I got an error on third line of the following snippet:

editor.js, row 263 character 5

The error is something like "Action not valid for the object" (rowly translated from italian).
If I continue to debug I noticed that

return false and skip the code inside.

Hello,

I have found a fix, remove the following line and it will works :

So, maybe this whole problem (and the reason why we have never been able to reproduce it here at www.kunena.org ) is because none of us uses Internet Explorer? Maybe the whole problem has to do with IE 10/11 Javascript support?

As it turns out, I passed the information to the developers and they checked. This change has been referred to at GitHub #2010.

Howard, can you tell us what kind of browser you have been using when you have the problem, please?

EDIT:

Further information:

1. Howard uses Safari
2. json support enabled; json version 1.2.1
3. Cannot reproduce these problems at www.kunena.org

A comment on using the Kunena 1.7 template:

Kunena 2.0+ is designed to use CSS, JS and image files from the "legacy templates", but to ignore any PHP code. So the Blue Eagle derived legacy templates should work, althought with some potential issues.

In this case I would just keep using the old one, but at the same time I would remove all the javascript and PHP files, just in case. Then I would rename the template and change its version. Of course this should be done first in a test site...

Further update:

1. I talked for about an hour with Howard
2. Howard is now trialling K 3.0.3-DEV to see if it makes any difference
3. Howard promised me that he will never again use the K 1.7.2 Blue Eagle template
4. Howard will be building a "vanilla flavoured Joomla" test site (with no changes, no non-standard Joomla site template, nothing else added), install Kunena on it (again, with no changes to the configuration) and see if, out-of-the box he can reproduce the message preview issue. This could take a while before he gets back to us.
5. This is a low priority issue as far as Howard is concerned.

Further update: Howard confirmed that on a "vanilla-flavoured" no-frills Joomla website, with a vanilla-flavoured K 3.0.2 installation, there were no issues with the message preview. This eliminates the webhost as a possible cause and also eliminates Kunena software as a possibility.

The cause is therefore, in this particular case, something unique to Howard's installation. We can probably consider this matter closed for the time being but it would be nice to know what other Joomla extension, installed on the problem site, interferes with the behaviour of Kunena's editor.js ... in this particular instance.