I am trying to create a smart group for contacts that have activity added by specific person.
Advanced search allows me to search either (1) for contacts based on some activity; (2) for activities based on who has added the activity.
But unfortunately not for contacts based on who has added the activity.
UPDATE: (Tested on CiviHosting demo site.)
Advanced search parameters:
Display Results As: Contacts
Basic Criteria - Complete or Partial Name: Errol
Activities: (*) Added by
RESULT: Search returns Errol as the only result, not all contacts whose activities have been added by Errol.