e-Newsletter not saving "Email content"

I have followed the instructions and set up the e-Newsletter plugin settings, created a newsletter. The problem is that it is saving all newsletter settings EXCEPT for the "Email content" - it saves the Email title, branding etc - but not the Email content.

I suspect it is an AJAX issue? Because when any edit is made to any of the other boxes (title, branding etc) then the top blue "Saved" button changes to "Save Newsletter" - but when any changes/edits are made in the "Email content" box, the button does not change. It is like the script is not recognising the changes in the Email content box?

Any help please?