Exception when run for the first time with no current wallpaper image

Exception prevents Variety from starting when running it for the first time when no wallpaper image is set, or when it is not possible to obtain the wallpaper image (e.g. on obscure DEs):

INFO:variety: process_command() ‘Received command: ['-v']‘
INFO:variety: load_banned() ‘Missing or invalid banned URLs list, no URLs will be banned’
WARNING:variety: load_history() ‘Could not load history file, continuing without it, no worries’
Traceback (most recent call last):
File “/opt/extras.ubuntu.com/variety/bin/variety”, line 46, in
variety.main()
File “/opt/extras.ubuntu.com/variety/variety/__init__.py”, line 87, in main
window.start(arguments)
File “/opt/extras.ubuntu.com/variety/variety/VarietyWindow.py”, line 117, in start
self.thumbs_manager.mark_active(file=self.used[self.position], position=self.position)
IndexError: list index out of range