Introduction of Monitoring->Problems in 3.2 had a goal of hiding such technical and internal terms as "trigger" and "event" from end users. ZNXNEXT-104 introduced Close problem option for acknowledgement. And yet, Configuration->Event correlation uses old "event" word.
It will be good for consistency and clarity to rename "Event correlation" to "Problem correlation", because only PROBLEM events are actually correlated. Same goes about correlation rule conditions and operations. "Old/New event tag" -> "Old/New problem tag", etc. "Close old/new event" sounds wrong. "Close old/new problem" is more correct and more descriptive.