When using display scaling with multiple monitors, there is a small (1px) overlap between the monitors. To reproduce: 1. Have 2 monitors, set up in side-by-side 2. Go to display settings, and set both to Custom (0.6 for both x/y) 3. Press apply (then keep) 4. Drag them so they're still side-by-side 5. Press apply (then keep) again If you maximize a window on one monitor, you'll see a thin (1px) strip of it on the other monitor.