Hello alek, here I have the same error with 0.9.91: The month list is appearing as an unstyled LI list.
I use Twenty Thirteen from the plugin’s theme set. In the sidebar widget.
The general problem is that the calendar allows to be browsed but is not changing the year number when you go back/forward with the arrows, nor even avoiding looking for past, unused years, if you continue clicking.
In regards of CSS look and feel…
– Calendrier styles OK.
– Pastel styles OK.
– Classic styles OK.
– Classic Dark styles OK.
– Twenty Twelve shows the unstyled months LI (https://docs.google.com/file/d/0B4ZIdz9VEIQGYUZZelRuZ1l1RDA/edit)
– Twenty Thirteen also shows the unstyled months LI
– Twenty Fourteen styles OK.
– Twenty Fourteen Light styles OK.
I reapplied the Save settings trick, and even tried switching themes but it is surely a bug in your CSS.
Hope you can fix it.
Best regards