There are options for how a second screen is handled. They can be pretty confusing! On my laptop, this is activated with Fnct F4. It will probably be a different key on your laptop. That brings of a choice of how you want to handle the two screens. I have never run two screens with my laptop but have run several screens with desktops. There you select settings/display and scroll down that screen. There you find settings for multiple displays and can address which is primary, how the mouse get from one to another, etc. Play around.