Thanks for trying... I've been dealing with this for many months and it's just annoying to me when I know it shouldn't happen. Maybe when I do my next fresh install of the OS and start from scratch it will get sorted but I'm doubtful as it happens on my other computer too that has totally different hardware/drivers. I wish someone else could reproduce this but now my hopes aren't too high for that either.

sound like the mouse driver isn't the issue since it's happening on two different machines. maybe a hidden process from an app both machines have in common. other than that i have no idea.

That's been my thinking but I've disabled all the things I can think of and turned off their processes that are on both machines and it still happens... It's been driving me nuts... though at my age it's getting to be a shorter and shorter drive.