i3TOUCH EXCELLENCE User Manual page 26

If the image on the computer display or the i3TOUCH is showing black borders, go to "control
panel -> display -> screen resolution". Choose the FHD (1920*1080) or 4K resolution
(depending on I3TOUCH). Then choose duplicate.
Now choose "advanced settings". Choose the tab of your graphical card control panel. In this
field you should see the options display, refresh rate, rotation and scaling.
26 i3TOUCH EXCELLENCE Monitor User Guide