I've been fighting mouse lag in 2.0 since day 1. Click...wait....click....wait.... Last night I decided to try something so simple that I didn't think it could possibly work; swapped out the mouse. Wham bam boom, no further issues. I'm 10 reboots and cold starts into testing so pretty confident.

Original mouse was a Microsoft USB mouse, your basic wired mouse. It seems fine in other OSs. New mouse is wireless HP "laptop mouse".

Might not work for you but very little lost in trying.