This is a bug in the lwjgl, Natives etc. You can't move, you can only look around, place blocks, destroy blocks and jump, escape and slash if you hold them for a long
What I thought was going to happen was I would be able move normally
What happened was I could only move in certain ways.
Steps to Reproduce:
1. Open minecraft with a Macbook
2. Move around a little
3. You will experience this bug
Environment
Put your operating system (Windows 7, Windows XP, OSX) and Java version if you know it here
Why reporting it here then?
LWJGL issues go to https://github.com/LWJGL/lwjgl.