User blog comment:DaNASCAT/Technical Update: January 3, 2012/@comment-4126310-20120104012501

When did things switch over, exactly? The visual editor has been unresponsive (only the edit summary field appears, everything else is grey) since about 0:20 UTC. It still worked on 0:10. I can edit Template pages, but that's just about the only thing I have access to. I suspect something is wrong with the visual editor (since the template namespace is all source).

Note: This only occurs with my primary browser, Opera. The editor works as expected with Firefox. I had a similar problem with a previous update, the one on November 2.