Fix Mavericks vertical scrolling lock? (jerky scrolling, accidental safari back)
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I made a quick app which hacks together some basic vertical-only scroll lock support. It basically tells the system to ignore small horizontal movements when scrolling in a mostly vertical direction.

You can download the app from http://kapeli.com/ScrollLock.zip. The source code of the app is available at https://github.com/Kapeli/Mavericks-Scroll-Lock.

I have no idea how well it works, only barely tested it, but it will prevent horizontal movement when your scroll