item_factory should not be stored as class ivar, because its value then fails to propagate to subclasses

[david]

[adsteel]

@david Could you elaborate on this issue? I'm not sure why we'd want instance variable values to sync across sub-classes.

[david]

@adsteel if you have list widget classes you want to inherit from, the item factory won't propagate, so it's basically a reuse issue.