How do I choose the main screen, mirror displays and arrange my desktop?

How do I choose the main display?

1. Expand the display you want to make main.
2. Open Use as.
3. Choose Main display.

Radar Display makes that display the desktop's main screen. If it was a mirrored display, it first leaves the mirror relationship. The app preserves the screens' relative layout while moving the desktop's origin to the new main display.

The main display has no Position picker. Set the other displays' positions relative to it. To stop using a screen as main, choose Main display on another screen; Extended display is not necessarily offered on the current main screen.

An active iPad can also be made the main display. Keep a working physical screen available, particularly while disconnecting or troubleshooting the iPad.

How do I extend or mirror a screen?

1. Expand the screen whose role you want to change.
2. Open Use as.
3. Choose Extended display to give it its own desktop area, or Mirror for [display name] to show the target display's desktop.

The picker lists valid choices for the current display setup. To leave mirroring, choose Extended display or make that screen Main display, whichever is offered.

A mirrored screen does not have a separate Position control. Extend it before placing it beside another screen.

Radar Display can make an iPad mirror a physical display. It does not offer the iPad as a new mirror target for a physical monitor. Display names in this menu use the detected names, even if you have added custom names.

How do I place a screen to the left, right, above or below?

1. Expand an active, extended display that is not the main display.
2. Open Position.
3. Choose Left of [display name], Right of [display name], Above [display name], or Below [display name].
4. Move the pointer across the shared edge to check the result.

The screens are placed edge to edge and centered along the other direction. For example, Right of MacBook Pro puts the selected screen immediately to the MacBook's right, with their heights centered.

The app offers relative placements rather than a draggable map or numeric offsets. If you want a particular vertical offset, adjust the arrangement in macOS System Settings. See the next section for how reconnecting interacts with saved Radar Display positions.

How do I arrange three or more screens?

Build a chain using the screen next to each display as its reference. For a MacBook, a monitor, and an iPad arranged in that order:

1. Make the MacBook the main display.
2. On the monitor, choose Right of MacBook Pro in Position.
3. On the iPad, choose Right of [monitor name].

Use the actual names shown in your pickers. This gives each display a different neighboring screen.

If you put a second screen in an occupied position, Radar Display inserts the new screen next to the reference screen and moves the existing neighbor farther out. For example, choosing Right of MacBook Pro on the iPad when a monitor is already there places the iPad between the MacBook and monitor.

The menu omits equivalent names for the same gap. For example, if the iPad is already right of the MacBook, an option immediately left of that iPad can describe the same gap as Right of MacBook Pro; use the placement offered in the menu.

Changing the main display reorganizes the saved relationships to preserve the layout. Choices that would form a circular chain are reconciled around the latest placement. Check the result after changing several relationships rather than assuming every older position remains unchanged.

What does Automatic do, and what happens after reconnecting?

Automatic removes that display's saved relative-position rule. It does not immediately move the screen or restore a previous layout. Other displays' saved rules can still refer to it.

Radar Display reapplies saved position rules when displays become active again, such as after reconnecting a monitor, returning its input to the Mac, opening the lid, or reconnecting Sidecar. A stored reference to a temporarily absent screen is retained so it can work when that screen returns.

Dragging screens in System Settings while they stay connected is respected at that time. A later reconnect can apply Radar Display's saved position again. If you want macOS to retain your manual layout without a Radar Display rule for that screen, choose Automatic for it.

Selecting an already selected Position is a no-op; it does not force the desktop back into that geometry. To change a position, select a different placement.

How do I label two similar monitors?

1. Right-click the display's row and choose Edit Custom Name…, or expand an on display to use its Custom name field.
2. Enter a useful label, such as “Desk left” or “Console monitor.”
3. Press Return or leave the field to save it. Closing its editor also saves the entry.

The custom name appears as a secondary label beneath the display's detected name. It does not replace the detected name in Position or mirror-target menus. Hover over a truncated detected name or custom label to see its full text.

Names have leading and trailing whitespace removed and are limited to 80 characters. Clear the field to remove the custom label. The field's placeholder is Optional. The right-click editor also works for a present display that is switched off.

Custom labels are saved for recognized displays, including iPads. They help you distinguish rows but do not improve hardware matching when two monitors lack distinct identifiers.