Remote user or browser plug-in
A few days ago I was using Safari browser on an iMac( 2016 version running Sierra) when I had to fight for control of the mouse. It seemed there was a remote user fooling around with the browser opening menu items, checking out bookmarks inthe favorites bar, and even deleting a bookmar and closing a tab. I was able to close all open applications and shut down the machine. I waited and then rebooted and everything seemed back to normal. I did a complete scan and nothing was detected. How can an intruder get in the machine undetected like that? It only seemed to affect the browser.