Like the Inbox which has a number in parenthesis which indicates unread
messages, the Calendar has a number also in parenthesis which indicates
calendar items added to your calendar which have not been
opened/closed. You can right-click on Calendar and choose "Mark All As
Read". Unfortunately, in our workplace (400 users) when doing this the
number usually dissappears while users (including my own Calendar) a
number remains such as (1) or (3). I have done various filtering to
find these calendar items but with no luck. Any ideas out there on how
to get rid of the number in parenthesis?