Comment 3 for bug 856669

Both the simple and the GtkBuilder test cases for the original bug still work (it was wrong at the refcount check, though; the builder has a reference, and the python code has another variable for it, so it ought to be 2), so they still work. I confirm that with 3.0.0 custom constructors are still called, so this must be something else. I'll try to distill a test case for this.