Is LingQ now blocking Ctrl+F on its lesson pages?
I’ve experienced the same issue. (FF on Windows XP)
Not intentionally, no. We’ll have to look into this once we’ve addressed some of the more major issues.
I don’t know how LIngQ runs its audio, but often with Flash-based audio or video the usual shortcut keys do not work after running the audio/video. However, clicking on some part of the page not part of the Flash area will allow the keys to function again. Maybe that is happening here? It may be worth a try.