Hello Arthur,

Indeed, for the time being double click events are not exposed on the grid core and on the grid selection behavior. This will certainly be addressed in next releases of the product, meanwhile you can use something like this to attach double click event on grid row (in this particular example I am attaching double click event on the third row of the grid)

            var grid = $find("<%= WebDataGrid1.ClientID %>");
            var gridRow = grid.get_rows().get_row(2);
            gridRow.get_element().ondblclick = function() {
                alert("Double click");
            }