Must appear in the GROUP BY clause or be used in an aggregate function
Symptom
Red blinking outline on Query after adding data and computing an aggregate, e.g. Sum, Count, Max. Display logs shows the journal entry highlighted here:

Underlying cause
Number of values don't synch up resulting in an error when adding data to the temporary worktable.
Fix
Edit additional data and (1) Check the Group box for any columns that do not contain aggregates, and (2) Click Advanced parameters and check Group data by the targeting dimension element.
Preventative
When adding additional data and computed aggregates in a Query, maker sure every column in the worktable is an aggregate or Group by, including the targeting dimension.
