Recently, I was asked about a question that how to roll back the Selection Security to be Enable again.
It looks like on the Dashboard Properties page, you could change the Selection Security from Enable as shown by the graph above to the two new icons below which offer more flexibility of setting up the selection permission.
In order to roll back the change, you need to go to the catalog Manager and navigate to Shared -> Shared folder name (eg: BI Framework) -> _Portal
Go under _portal folder and find the dashboard folder that the change was made. You would see there is one extra folder called _selections and one extra attribute file _selections.atr
Delete these two items and restart BI Server. You would see the Enable link is restored back!