[pygtk] PyGTK object escapes garbage collection

[Hrvoje Niksic]

The problem you describe sounds like it might be related to this 
infamous PyGTK bug:

https://bugzilla.gnome.org/show_bug.cgi?id=546802

In our tests the problems show up when a Python object that participates 
in a cycle is referenced only through a GTK widget.  When GC takes 
place, Python's cycle-breaker incorrectly concludes that the whole cycle 
is unreachable and runs tp_clear on all objects.  The objects are, of 
course, still reachable through PyGTK, and unfortunately now quite broken.

A number of workarounds are available: simply access the widget's 
__dict__, which forces it to switch to a different reference-counting 
strategy.  Or store a reference to your object in a global variable or 
container.