To reproduce: 1. Uncheck all your calendars. 2. Add an event 3. Notice it shows up in the main view (month/week/day whatever) It shouldn't show up, since none of the calendars are selected.
*** This bug has been marked as a duplicate of 168495 ***
Mass move of libxpical bugs to the Internal Components, per ctalbert.
The bugspam monkeys have been set free and are feeding on Calendar :: Internal Components. Be afraid for your sanity!