div x_mainHolder stays hidden

We use Xerte version 2.0 (svn r1037) and experience a trouble since some days:

The navigation structure is not displayed when opening a module.
I looked into the source code and found xenith.js might be responsible for this.

It sets div x_mainHolder to hidden on document.ready.
The function x_setUpPage would set this div to visible again but is never called.

e.g. xerte.livewell-community.eu/play.php?engine=html5&template_id=6

Any help or idea would be highly appreciated!
Thank you in advance

I think this is likey to be due to the mathjax issue see this thread:
xerte.org.uk/index.php?option=com_kunena...3&Itemid=207&lang=en

Thank you very much Ron!
I'd like to add that in exported modules the script reference is placed into index.htm
I downloaded Mathjax.js and its extensions, placed it locally, changed the references in my 56 index.htm and everything seems to work.

Hi Gerhard
yes previously exported projects will have the same issue but you shouldn't need to download mathjax etc and arguably a better option is to fix the links in your install and then re-export. The export will then have the correct link to mathjax. For just one or two exported projects changing the mathjax link in index.htm might be quicker.
In this instance the issue has been caused by a change with the external mathjax source but in recent months and years there have been changes on YouTube, Flickr and others and all are fixed in the Xerte code quite quickly so it's always easier to keep an installation up-to-date than large numbers of exported projects.
HTH
Ron