Showing activities performed by specific users, tags or another approach?

Hi forum,
I’m using AppOne 21.10

My goal is to show in the process graph which activities where performed by a certain subset of users, and which where made by ordinary users.

A specific character in the beginning of their call name distinguishes the said users. A simple expression can identify them:

if(Left(CallName,2)="Character ",“Specific users”,"Ordinary users”)

I have been working for hours trying to construct one without any luck. The first expression has a Number of records above 250.000. That’s the total number of events.

The expression for the tag (see below) counts ca. 20.000 records. I don’t understand why, and that is probably one of my main problems :smiley:

First of all, is a tag the correct method for highlighting activities by these users?
Secondly, I hope someone can help me understand what I am doing wrong. At the very least, both kinds of users should be visible in the tag expression?!

Best regards,