This all started with me trying to get 2-finger scroll working. In Windows, I got used to it. So I found a thread that said to run these commands:
synclient VertTwoFingerScroll=1 synclient HorizTwoFingerScroll=1 synclient EmulateTwoFingerMinW=5 synclient EmulateTwoFingerMinZ=48
It kinda worked, when I put one finger extremely close to the other. So another thread said to fine-tune the MinW and MinZ by doing
synclient -m 150, where I got the error "Can't access shared memory area. SHMConfig disabled?"
So I set off to enable SHM Config. I found another post that said to edit my /etc/X11/xorg.conf file and add
Option "SHMConfig" "on" - so that's in there, and I still get that error. My mouse is all over the place almost any time I touch it at this point!