After collecting measures from a summary table, how do I control when the measures?

Measures collected from a summary table are supposed to update automatically whenever the summary table changes. In general, there isn't a way to prevent the measures collection from updating in this circumstance. Unlike measures collected from another collection, there is no Collect Measures pane in the inspector for measures collected from a summary table. If you want to remember the current set of values you can copy the cases from the measures collection to a new collection, which will not update when the summary table changes. Alternatively, you may be able to achieve what you want by creating measures in the source collection that correspond to the formulas in the summary table and then collecting measures from the source collection instead of the summary table.