Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/utils.py", line 85, in <lambda>
    glib.timeout_add(500, lambda: wrapper(*args, **kwargs))
  File "/usr/share/software-center/softwarecenter/utils.py", line 90, in wrapper
    f(*args, **kwargs)
  File "/usr/share/software-center/softwarecenter/view/widgets/carousel.py", line 174, in _build_view
    self.view._cleanup_poster_sigs()
  File "/usr/share/software-center/softwarecenter/view/catview_gtk.py", line 258, in _cleanup_poster_sigs
    for poster in self.whatsnew_carousel.posters:
AttributeError: 'NoneType' object has no attribute 'posters'