Alert messages with difference between problem & resolved

[Sypher]

I'd like to have the time it took to resolve an issue. We receive both "problem" and "resolved" messages, but how can I show "it took hh:mm:ss before this issue was resolved" in the email?

[zabbix_zen]

Unfortunately,
that's still only possible using Escalations..
Can't recall if there's already a Ticket for having that in Zabbix 1.9.x