answer:I know some laptops have hotkeys to change the way their displays work (usually rotating/inverting them), and that the lower-right corner of a full-screen browser window is right near the controls for stuff like volume or display drivers. Apparently you “fat fingered” something that is rather unique to your setup. As I don’t use a second monitor on my laptop, I can’t really say for certain, only give you a few random thoughts in the hopes that they help lead to a solution.