Filesystem view not available

Binary package hint: quodlibet

Open quodlibet and go menu->view->filesystem.
Nothing happens, and after quodlibet is closed it will no longer open.
This is shown on the console:

Traceback (most recent call last):
  File "/usr/bin/quodlibet", line 301, in ?
    main()
  File "/usr/bin/quodlibet", line 45, in main
    window = widgets.init(player, library)
  File "/usr/share/quodlibet/widgets.py", line 81, in init
    main = QuodLibetWindow(library, player)
  File "/usr/share/quodlibet/qltk/quodlibet.py", line 245, in __init__
    self.select_browser(
  File "/usr/share/quodlibet/qltk/quodlibet.py", line 518, in select_browser
    self.browser = Browser(library, player)
  File "/usr/share/quodlibet/browsers/filesystem.py", line 67, in __init__
    dt = DirectoryTree(initial=const.HOME, folders=folders)
  File "/usr/share/quodlibet/qltk/filesel.py", line 68, in __init__
    folders = filter(is_folder, folders)
UnboundLocalError: local variable 'is_folder' referenced before assignment