title: Expand/Collapse button in a Silverlight DataGrid
body: <p>I am using a RowDetailsTemplate in a Silverlight DataGrid to show row details. Setting RowDetailsVisibilityMode="VisibleWhenSelected" does not give a good user experience (only one row can be expanded at a time, all rows cannot be collapsed). What's the easiest way to add an expand/collapse button on each row so that the rows can be expanded/collapsed independently?</p>