[otrs] Notification about new Tickets in AgentFrontend

Hello list, I'm searching for the switch in SysConfig where I can turn on the notification about new tickets and / or followups for non-locked tickets in the AgentFrontend. I am notified by email about "my queues", but when I am already logged in to the AgentFront, I don't want to follow the link in the notification email but want to be notified by the Frontend itself. This notification works well for tickets which are locked by my account. Where do I find this configuration option (I guess, it is one)? Thanks in advance Markus Nagel