I'm trying to use the TeX filter and I have exactly the same problem. When I go to "Settings>Site Administration>Plugins>Filters>Manage filters", all filters raws are disabled and greyed out. It's impossible to click into the "disabled" box, so imposible to turn it on. I get the same result in "Settings>Site Administration>Plugins>Plugins overview".
General help
Youtube videos is disabled under Manage Repositories
This discussion has been locked so you can no longer reply to it.
