Assigning an app to a desktop is an app-level rule. It is useful when nearly every window from that app belongs in the same Space. It is a poor fit when one browser, editor, or document app serves several projects.
Set the app-level assignment
Create or select the destination Space, Control-click the running app’s Dock icon, choose Options, and inspect Assign To. Apple provides choices including This Desktop, All Desktops, a display-specific desktop when available, and None.
Test by opening another ordinary window from the app. Confirm which desktop it appears on and whether application switching moves you there.
Move one window instead
To relocate only one existing window, enter Mission Control and drag that window to another desktop thumbnail, or drag it to the edge of the screen and wait for the adjacent Space. This changes the selected window’s location without declaring that every future window from the app belongs there.
Choose the narrower rule
| Situation | Better choice |
|---|---|
| Communication app belongs everywhere | All Desktops, if that is truly desired |
| Dedicated app belongs to one context | This Desktop |
| Browser has different client windows | Move individual windows |
| Need cross-Space project identity | Add a project group or clearer titles |
App assignment controls desktop placement, not account identity, task ownership, or saved-session restoration. Review it when the app begins serving more than one project.