Sorry Daniel,
Maybe, I'm not really clear. I'll try to be more
Once, I thought that the problem come from an uncompatibility between JoomlaComment and the Login Module of JFusion.
After some tests, I notice that if I turn OFF mod_comment, the login from JFUsion works, so I suppose that the problem comes from mod_comment.
After that, you tell me to desactivate all Ajax calling and I turn OFF ultimate display module and ON mod_comment.
So, when we look at that, the problem seems to come from an uncompatibility between mod_comment and Ajax ?
I'm more clear ?