@hannes2peer @vinzv @marcus On occasions I think I've had to reload the page (because some user-specific setting wasn't saved? (yet?)) before being able to access either the !qvitter or #classic interface. Not sure how to reproduce consistently.
Most likely I've just confused myself with multiple open tabs and I've probably just been too fast for the force-layout-mode setting to save.
I always want to make sure that people have disabled any Memcache like plugin when weird stuff like these occur.