How To Enable Middle Button Scrolling For The Lenovo X220 On OpenBSD

Add this to your .xsession or .xinitrc file:

xinput set-prop "/dev/wsmouse" "WS Pointer Wheel Emulation" 1 
xinput set-prop "/dev/wsmouse" "WS Pointer Wheel Emulation Button" 2 
xinput set-prop "/dev/wsmouse" "WS Pointer Wheel Emulation Axes" 6 7 4 5

Then restart X! :D

(This probably works on other Lenovo laptops with the middle button but I've only tested it on the X220)