You should be able to control this functionality using the Web Report Studio roles. The capabilities that you want to control are beneath the "OLAP" category. In this category you can enable or disable the following: Drill, Drill to Detail, Expand and Collapse, and Expand And Collapse All. Note that if you want to enable or disable specific features for certain users, we recommend that you create a custom role. We recommend this because there is no way to return to the 'out of the box' settings after you have modified one of the built-in roles.
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