Choose a small set of clear rules
Start with two apps whose needs are obvious. Confirm that every target input source is already enabled in macOS. A rule selects a macOS input source; it does not change an input method’s internal Chinese/English mode.
Add an app and select its input source
- Open the app rules page.
- Choose “Add App…” and select the installed app.
- Select one enabled input source for that app.
- Repeat only for apps that need an explicit rule.

Turn on automatic per-app switching
Enable “Follow active app,” then move between the configured apps. Enabling this mode stops input source locking so the two automations cannot compete. Quitting Input Method Manager stops automatic switching.
If results appear inconsistent, temporarily turn off “Automatically switch to a document’s input source” in Text Input settings and test the app rules again.
Handle moved or removed apps
If an app is removed or moved so the saved rule can no longer identify it, the rule is marked unavailable. Use “Check Again” after reinstalling or moving the app. Delete rules you no longer need.
- Switch between each configured app three times.
- Confirm an app with no rule keeps normal macOS behavior.
- Quit and reopen Input Method Manager to confirm the saved rules return.