X2 click open form detail - Default Action property on grids
Default Action property on the form grid control was added in AX 2009. It allows to specify a menu item from the form which will be executed on the double click event on the grid. Originally this feature targets list pages – it allows to open details forms for the selected record on the list page. However, it can be used for any grid on any form. The only limitation is that grid should not be editable.