This has been in the game so long and causes so many issues. You appear to have a "hidden" cursor at some (all? I'm not sure of the causes or conditions) times that is moving around the screen, and clicking sometimes, for example, causes random things to be pinged on the map. I now realize that this is what causes "Incoming Damage" to frequently pop up and take up a ton of screen real estate when I'm trying to view a replay, since it's getting implicitly clicked when I'm trying to do other things.