The app opens its window and starts its engine on macOS 27. It used to launch to a menu bar and nothing else.
Reopening the app right after quitting it starts cleanly. The app waits for the engine its last launch left, and stops only that one.
Starting the app no longer stops other FabricLoom engines running on the same Mac.
Every launch writes a log file under ~/.fabricloom/logs, so a launch that goes wrong can be read afterwards. Logs older than 30 days are removed, and the oldest go first once the folder passes 100 MB.