CoCoA consists of two components, the engine and the interface. These two components are both running in separate threads and communicate asynchronously. Whenever the engine produces output, it posts an event to the event queue of the interface, which then processes these events. Let's explain this using a short example:
For I := 1 To 20000 Do Print I, " "; EndFor;After you execute this command set, the engine produces text events which are then processed by the interface. However, while the interface is processing these events, the engine might already have terminated. But if that is the case, there is not computation to interrupt anymore. And thus you can't stop the output from appearing.
showInteractiveDocumentCloseWarning=1of the configuration file (which is normally named .xcocoarc or wincocoa.ini) to a 0.