Diagnosis
You called the function "Sort SQL trace list". The system uses thefield on which the cursor is positioned as the sort field. However thecursor is positioned on a field that cannot be used for sorting.

System Response
The system continues its work after the message output.

Procedure
Position the cursor on the required sort field and repeat the action.
For sorting you can currrently choose one of the following fields:
Transaction (transaction code), PID (process identifier), Ptype(process type), Client and User (logon user).