Hi Isomorphic,

timelines tend to be very wide (and sometimes also high). In cases where the height is known to be less than a screen, a developer might want to set something like
mouseWheelScrollDirection: horizontal (while the default would be vertical). I'm not sure if this belongs on Canvas or Timeline, but I think such a setter might be useful.
I did not test current behaviour with a mouse with a 2nd horizontal scroll wheel as well. In this case the setter would basically switch the scroll directions for the two wheels.

This has no priority for me, I was just browsing samples.

Best regards