SYMPTOM:
Users have the ability to define derived elements on a report by right clicking on the attribute header or the attribute in the Report Objects window in Strategy Web 9.3.1. After unchecking the Web Analyst privilege 'Web define derived elements', users are still able to create derived elements on a report as seen in the image below.

STEPS TO REPRODUCE:

CAUSE:
This is a known issue in Strategy Web 9.3.1. Under the Web Professional group another privilege exists to "save derived elements." When this privilege is enabled, the user is still able to create derived elements.
ACTION:
Contact Strategy Technical Support for an update on this issue.
WORKAROUND:
Disable the privilege "save derived elements" from the Web Professional group as well as "define derived elements" from Web Analyst.
KB46440