I am applying "restrict category" because it fits well to my purpose. However, I found this plug-in conflicts with other event-calendar plugin, such as calpress calendar or all event calendar. After I activate and click admin-menu to allocate categories to each user role, it shows nothing. So I gave up to use calendar plugin and after I uninstall event calendar program, it is still unstable. In case of multi site(network), the first network site does not work but some other sites are working. Once after this plug in is not working, I cannot change it back. This is very confusing, Do you have any idea? How to fix it?