iOS/iPad apps on Apple Silicon Macs

An iPhone/iPad App Store build installed on an Apple Silicon Mac keeps the iOS scene lifecycle, not the desktop app model. This one fact drives every behavior below: a scene is foreground-active, foreground-inactive, background, or suspended, and a plain app runs code only while its window is visible on a connected display.

The visibility rule, not focus

Window mapped on a connected display → scene stays foreground-active and code keeps running, even if another app holds keyboard focus.
Minimize to Dock or Hide the app → scene enters background → the system grants a few seconds to save, then suspends it. The process stays in memory but executes nothing, so timers, automation, and a game’s simulation stall.

The axis is visibility, not focus. So an iOS-on-Mac app cannot run “in the background” behind other windows the way a desktop app does — but it also does not need to be the frontmost application. Only apps declaring a background mode (location, audio, VoIP, a few others) keep running when hidden; a game client does not qualify.

Off-screen parking via a virtual display

Moving a window to another display is not the same as minimizing it: the window stays mapped, the scene stays active, and code keeps running. So the technique is to keep the window visible on a screen you never look at:

Create a virtual display that is not mirrored onto the main screen.
Place it off to the side in System Settings → Displays → Arrange… — a region no physical monitor covers.
Move the window there when idle, back to the main monitor to use it.

The window is always “on screen” from the system’s point of view, so the app never suspends; it is simply on a screen no one can see.

BetterDisplay setup

BetterDisplay supplies the virtual display (brew install --cask betterdisplay, or the releases page). Add one virtual screen and set:

Connect this virtual screen: on — load-bearing. A disconnected virtual screen is not a display surface, so a window “on” it counts as hidden and the app suspends. The parking display must stay connected; disconnecting it to “save resources” re-triggers suspension.
Aspect ratio 16:9 so the parked window keeps its proportions; name is a free-form identifier. Keep resolutions ≤8K (higher can be unstable).

Then drag the virtual screen beside the main display in Arrange… and do not mirror it. Exact coordinates do not matter if the window-mover reads the live layout through CoreGraphics.

Moving another app’s window needs Accessibility

Programmatically moving another app’s window goes through macOS System Events, which requires Accessibility permission for the terminal (System Settings → Privacy & Security → Accessibility). Without it the move fails with an “assistive access” error (-1719) — a system gate that cannot be scripted around. BetterDisplay’s own CLI manages displays, not windows, so it is not a substitute for the window move.

Caveat

The suspend-on-background behavior is the observed behavior for a plain game client plus the general iOS-on-Mac lifecycle; an app that declares a background mode could differ.