Ticket counters serve the purpose of notifying agents about new tickets they might be interested in.
This is done by showing the number of tickets in a badge counter within the favicon and on the Tickets button in the menu:
By default every agent is subscribed to the "All Unsolved" filter.
You can "subscribe" to any number of shared and private filters in any combination.
To subscribe to a filter click on the ⋮ button and check 'Counter'.
Counter badges in your favicon and Tickets button will show the total number of unique tickets within the filters you're subscribed to.
If the total number of tickets is 100 or more, the badge counter will show '99+'.
Numbers don't seem to add up?
Every ticket only counts once. E.g. if you're subscribed to two filters that have 3 and 5 tickets respectively with 2 tickets in common, you'll see 6 (= 3 + 5 - 2) in the counter, not 8 (= 3 + 5).
The favicon counter works in Chrome, Firefox, Opera, IE11+ and Edge.
The button counter works in all browsers.