I thought the _Launch call to start a new program killed the current program, so I didn’t consider how to return to the original program. However, they my have changed that when MultiFinder was introduced.

I guess the proper way would have been to JMP to wherever a bare ‘G’ would have returned, not an RTS (if there is a proper way to do this kind of thing. I’m not sure the system guaranteed what you could do at that time. You might be in a memory manager call, which meant any drawing calls were off limits)

Fun memories.