It seems I introduced a new variable to my app, when I unblocked myself
working with NSTimers.
At the same time I figured it out, I also heavily refactored my
application and so now, have lost major functionality.
The current incarnation is attached. Before this, the python class
ZopeDocument and most of the code in its __init__() were in the
ZopeEditController's application_openFile_() method. Since refactoring
the class out, application_openFile_() never gets called. I suspect
that it might be the concurrent addition of the NSTimer object to sweep
the various files in play in ZopeEditController's init() method.