Main display

The main display is the screen macOS identifies as primary in the desktop arrangement. It can be different from the screen containing your pointer or focused window, so these are separate ways of choosing a target.

BetterDisplay uses main-display status in arrangement and targeting features. Making another display main changes system arrangement state; it does not merge the desktops or make them mirror each other.

You can also use that status as a reference point. Groups can protect a selected member's main status, while OSD settings can keep feedback on the main display even when another display is being adjusted.

See Management and Quick Toggles for the related management actions.