How to disable horizontal scrolling on OS X Yosemite's Preview? As stated in the question, how do I disable horizontal scrolling on Preview when the page obviously fits and there is over horizontal overflow?

I am scrolling with my touchpad, and with two-finger scroll I inevitably move a little sideways while scrolling. This little jerk to the left/right is rather annoying to me and I would like to know if there are any ways to prevent the horizontal scrolling.
I used to have the same problem and I solved it by cloning and building a fork of the Scroll-Reverser tool, whose repository is below.

https://github.com/dawncold/Scroll-Reverser

As you can see in this commit the author made a little patch in the tool in a way such that if you check the reverse horizontal scrolling option, it actually disables it instead of reversing it.

This is also explicitly stated by the author of the patch here.

You will need XCode to build the project and to generate the corresponding app.

Just as general information (the original author deserves it), the original Scroll-Reverser tool, which was doing just reversing instead of disabling, can be found here