The ID of a custom app is returned when you install
it. You can use matlab.apputil.getInstalledAppInfo to
get the ID after you have installed an app.
When a custom app runs, MATLAB® adds any folders
it needs to have added to the path, as identified when the app was
packaged. When the app exits, MATLAB removes those folders from
the path.
You can run multiple, different custom apps concurrently.
However, you cannot run two instances of the same app concurrently.