Window tabs on macOS: merging windows into tabs
macOS has had window tabs since Sierra and most people never find them. Here is how to turn them on, why the menu item is missing in half your apps, and what to do when the built-in version is not enough.
Short answer: open two windows of the same app and choose Window > Merge All Windows. To make it automatic, set System Settings > Desktop & Dock > Prefer tabs when opening documents to Always. This only works inside one application, and only in applications that support it.
Merging windows into tabs
- Open two or more windows in the same application — two Finder windows, say, or two TextEdit documents.
- From the menu bar, choose Window > Merge All Windows.
- Every window of that application collapses into one window with a tab per window.
To pull one back out again, drag the tab off the tab bar, or use Window > Move Tab to New Window. To move between tabs, ⌃Tab and ⌃⇧Tab.
Making new documents open as tabs
Open System Settings, choose Desktop & Dock, and find Prefer tabs when opening documents. Three choices:
| Always | New documents open as tabs in the existing window. |
| In Full Screen | Tabs only while the app is full screen. This is the default, which is why most people never notice the feature. |
| Manually | New documents always open as separate windows. |
Why the menu item is missing
If Merge All Windows is greyed out or absent, the application has not adopted the system tabbing API. That is a decision each developer makes, and a lot of them have not: most Electron-based apps, most terminal emulators, most design tools, and plenty of others. There is no setting that forces it — an app either implements native tabs or it does not.
Two other things commonly get mistaken for this feature:
- Safari's tab groups are a Safari feature for web pages, not window tabs. They organise browser tabs; they have nothing to do with grouping application windows.
- Stage Manager and Mission Control arrange and reveal windows. They never collapse several windows into a single frame with one tab each.
The limit worth knowing about
Even where native tabs work perfectly, they group one application's windows with that same application's windows. There is no arrangement in macOS in which a browser window and a terminal window share a tab bar.
Whether that matters depends on your problem. If you have eight Finder windows, the built-in feature is the right answer and you are done. If what you actually have is a project spread across an editor, a terminal, a browser and a chat app — four applications, one job — nothing in macOS collapses those into one thing.
Tabs across every app
Tack is a Mac utility for exactly that case. Drag any window onto any other window, hold for a moment, and they become a group with a shared tab strip — a browser, a terminal and an editor in one unit, switching like tabs, moving and resizing as one.
It works with applications that never implemented native tabs, because it arranges windows through the macOS Accessibility API rather than waiting for each app to cooperate. That is also why it asks for Accessibility permission the first time you run it.
If you are arriving here from Windows, the closest comparison is Stardock's Groupy — there is a fuller write-up of what Mac users coming from Groupy should know.
Try Tack free for 14 days → The full app, no account, no card. Then $39.99 once for up to 3 Macs.Common questions
Why is Merge All Windows missing?
The app has not adopted the macOS tabbing API. It is opt-in for developers and many apps skip it.
Can I put two different apps in the same tabs?
Not with the built-in feature — it is single-app only. That needs a third-party grouping utility.
How do I split a tab back out?
Drag it off the tab bar, or Window > Move Tab to New Window.
What is the shortcut for switching tabs?
⌃Tab for the next tab, ⌃⇧Tab for the previous, in apps with native tabs.