camera flips itself upside down in flask detached UI when orbiting

[agurvich]

when camera changes orbits it instead flips upside down and reverses orbit, very disorienting. easily demonstrated in person, @ageller

[agurvich]

update: it only happens when you can see the green/red face of the cube-- not sure which axes it's crossing when you can see those faces

[ageller]

Fixed. I forgot to set camera.up in viewer. I did that, and now it works.