>Why don't you simply step through the code with the debugger?

I can not - that's the problem. I opened the debugger, but how can I simulate the shutdown signal? The _screen.ControlBox = .f.

and when I tried to do from another session

do KillVFP, it closed both VFP windows and that's it. I even lost all my Command Window History.

UPDATE. I think I got it - found a bunch of problems, fixed them.

UPDATE2. When I try to debug it, I get 'Cancel or Suspend are not allowed'