It's as if an alien entity has commandeered the trackpad, and it highlights things when it has not been asked to do so; the mouse jumps erratically all over the place, AND opens up random windows unbidden. In this state it's nearly impossible to write anything on the computer in this condition. Guidance, anyone? MacBook Pro Mac OSX 10.6.8 TenQ
I was having the same problem with on my Retina. Rebooting and SMC reset didn't help.
Surprisingly I was able to fix it by pressing down hard in each upper corner as recommended in this Apple Communities thread. According to it the problem is due to pressure on the trackpad and pressing down resets/releases that somehow.