TL;DR. Each display has its own Ribbon strip. The laptop and an external monitor do not share one row. ⌃+⌥+N sends the focused window to the next display. Turn on “Displays have separate Spaces” so the strips and the pointer stay aligned.
Direct answer
Ribbon builds one horizontal strip per screen. A window on the monitor never scrolls the laptop strip. That keeps multi-monitor desks predictable when each screen has its own set of apps.
How multi-display behaves
| Action | What happens |
|---|---|
| Focus | Stays on the display you are working on |
| ⌃+⌥+N | Moves the focused window to the next display’s strip |
| Unplug a monitor | macOS moves windows; Ribbon rebuilds that strip |
| After restart | Session restore puts columns back when windows still exist |
Mission Control setting that matters
Open System Settings → Desktop & Dock → Mission Control. Enable Displays have separate Spaces.
A single Space stretched across every display makes strips fight the pointer. Ribbon’s Mac Setup check reads the current value and links you to the setting when it is wrong.
Practical layouts
Laptop + one monitor. Put the IDE on the large screen strip. Keep chat and mail on the laptop strip. Jump with ⌃+⌥+N when a window belongs on the other side.
Two externals. Treat each as its own row. Avoid dragging windows across displays hoping for one shared strip; that model is not how Ribbon works.