I have a model-view-controller widget.

When the app window closes, it releases the controller. At that point, the controller is set to nil. Then, a microsecond later, it a whole bumch of other events, like #deactivate and #MouseExit, and a new controller is created to handle them. I think somebody forgot that #controller method creates controller if it has none.

I would not care, but my controller starts a thread that gives it a "tick" capability. So when a new instance is created, it's started anew!

Wonder what I should do about (apart from movin the thread into a separate class, which I will do anyway)

Visual Works is a Smalltalk environment. C++ is nowhere near the code I am talking about.