Calendar week display
When you visit the calendar by going to http://localhost:8080/calendar (or wherever your calendar is installed) you'll see the weekdays of the current week displayed in the first row of the calendar view: Move forward by clicking right arrow button until you reach next month button. Click on right arrow button again. You'll see the week displayed in the calendar header stays at the week when the month changed, no matter if you click back or forth - it's frozen: