it should just close the window on macOS or Win
it could optionally close the app if it is the last window open, but that would depend on the app itself
Depends on the app… if it can (should) open another document via the menu, then don’t close it.
otherwise set APP.AUTOQUIT=TRUE in APP Open, and it will handle it automatically for you
The standard on Mac is to leave the app running so it can open the next document quickly. The standard on Win is to close the app and free up resources. You can override it by setting AutoQuit on either platform.