title: WPF DataGrid MultiColumn sort without shift key
body: <p>The WPF DataGrid has a default behavior of allowing multicolumn sorts when the user shift-clicks on multiple column headers. Is there a way to change this behavior so that the Shift key is not required? I have already handled the sorting event on the datagrid so that each column will cycle between the three sorting states (Ascending, Descending, and No Sort) and this is all working as expected as long as the shift key is held down, but I would like to make it so that the DataGrid does not reset the sorting on all other columns if the user clicks a column header to add a sort without pressing shift.</p>