This same thing is happening to me. When I have my ownCloud calDAV calendar synced, I click on the date in wingpanel, and it opens and then immediately closes and wingpanel appears to reload. When I uncheck my calDAV calendars (2 from ownCloud), the wingpanel 'calendar dropdown' works fine.
This same thing is happening to me. When I have my ownCloud calDAV calendar synced, I click on the date in wingpanel, and it opens and then immediately closes and wingpanel appears to reload. When I uncheck my calDAV calendars (2 from ownCloud), the wingpanel 'calendar dropdown' works fine.
Using Loki 0.4.