This worked up until May 16th. Before and after updating to macOS Sierra 10.12.5 did not solve problem.

Config / Specs:

  • MacBook Pro
  • Dell monitor
  • iPad using Duet app

Previous functionality

I could expand fullscreen any app/program in Mac (the green button top right) and use 3 fingers on the trackpad to toggle between 'screens' on that individual physical screen.

Current bug

When I fullscreen an app on one display and swipe with three fingers, swiping controls all 3 physical displays. The display in question swipes to the app, but the other two displays also swipe to the right showing blank black or white backgrounds and are mouseover-able.

Desired functionality -- the Previous Functionality

Swiping on a screen only controls that display.

  • Suddenly, I'm bothered by this 'bug' starting today - never experienced it earlier. macOS Catalina, 10.15.7. The setting "Displays have separate Spaces" is on (for ages). Jan 19, 2021 at 12:52

1 Answer 1


System Preferences → Mission Control and enable Displays have separate Spaces.

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