What platform are you on?
A couple of people have had the issue with not displaying usage. Please PM me an email address and I will send you a vsmerge with some debug in it, hopefully we will get to the bottom of it.
I will have to look into the mouse issue.
Smart Merge uses the difference engine to try to resolve some conflicts. An option was originally put in for this because it could affect performance, but it is very old and on a modern machine I would just leave it on.