User blog comment:DaNASCAT/Technical Update: June 5, 2012/@comment-1656630-20120607181744/@comment-1656630-20120608205527

Rappy/Ciencia: The new search structure didn't play well with the old preferences options, so we needed to remove them and rebuild the high priority ones. Special:Preferences is an ever-moving target as we change aspects of the site, and we want to keep the collection clean, relevant, and organized. Please keep us aware of what preferences are important to you and for what reasons, and we'll keep researching the impacts they have on user experience and tech configuration.

Kuopiofi: We just pushed a fix that we think might help. Can you clear cache, restart your browser, and tell us if it's better?