What to intercept for an OS closing of a stack to lock messages

[Dr. Hawkins]

I find that, even knowing better, I tend to close my output stack with
the OS controls (red button on Mac).

It seems that messages are being processed; it takes, at best, several seconds.

I've tried intercepting closeStack and destroyStack, with no luck.
What can I do to lock messages when this happens?

-- 
Richard E. Hawkins, Esq.
(702) 508-8462