When user has a few opened browser Zabbix tabs, then it's a problem to identify, which tab has received notification. It'll be awesome, if Zabbix can visualize notification, during this notification.
1.) change favicon - see Gmail, it changes site favicon
2.) add some related char into site title - see YouTube title during playing
Zabbix can use UTF-8 chars:
? - it indicates warning
? ?? ? - it indicates sound of notification
Examples are in the attachment.