Lenovo IdeaPad S540-15IWL User Manual page 20

You can change the settings for both the computer display and the external display. For example, you can
define which one is the main display and which one is the secondary display. You also can change the
resolution and orientation.
Note: If you set a higher resolution for the computer display than the external display, only part of the screen
can be displayed on the external display.
14
Lenovo IdeaPad S540-15IWL User Guide