Steps to reproduce:
- you have a wiki with multiple users, multiple goups and custom rights
- install LDAP application using EM (http://extensions.xwiki.org/xwiki/bin/view/Extension/LDAP+Application)
- after installing it, Rights are reset to default (blank white boxes), but NO user except admin will be able to login. It's like the default empty box is actually a deny.
- you can easily corrupt an entire wiki farm by doing this
I reported this here since I had no better place for it, since it's not the actual code of the LDAP Application (I think). I think it is because LDAP Application has a dependency for XWiki Platform - Administration which is re-installed, overwriting existing settings.