Did this ever get fixed? I still have this problem with the MergeEdit sample page, it works if I use it onsite at WikiTree, but if I download it and serve it, even unchanged, from another site, it does not work, I get an error page that says 'already logged on'.
I have found it is possible to initiate the MergeEdit by encoding all the parameters onto the url and calling window.open(url), but, that does not work with longer (i.e. typical) bio markup text as the url length limit is exceeded.
Any help with this?