Why does a bright pointer have a halo on my mini-LED display?

A bright pointer against a dark background can reveal the display’s local-dimming zones. Each backlight zone covers many image pixels, so lighting the pointer can also illuminate the area around it. This is commonly called blooming or a halo effect.

Higher brightness can make the effect more noticeable. Compare the same dark scene at a lower brightness and with brightness upscaling disabled. Choose the setting that makes the surrounding glow less distracting.

BetterDisplay cannot make the panel’s physical backlight zones smaller. If your monitor offers its own local-dimming setting, compare the available modes using the monitor’s instructions. Some displays have no adjustable local-dimming setting. Turning local dimming off can also reduce contrast.

Apple’s explanation of mini-LED local dimming describes why a backlight zone larger than an LCD pixel can produce blooming. A pointer that merely stays bright while the desktop is dimmed is a different issue. See software dimming and the cursor.