Mouse rotation axis when redefining camera.up with OrbitControls

Hi all,

I’m trying to tilt the camera using OrbitControls by changing the camera.up property and calling controls.update(). The view is updated as intended but if I then rotate the camera by clicking and dragging with the mouse, a horizontal movement of the mouse doesn’t result in a horizontal rotation of the scene, i.e. the rotation axis doesn’t seem to match the camera.up vector.

I’ve created the following fiddle to illustrate my issue (the code that tilts the camera starts on line 69):

How can I achieve the desired behavior?