fires the moment you drop the column over the target area
| sourceId | string | the source column id |
| targetId | string | the target column id |
| event | Event | the native event object |
$$("datatable1").attachEvent("onBeforeColumnDropOrder",
function(src, targ, event){
// some code
return true;
});
The event is blockable. Returning false will prevent column from being dropped if the order mode is enabled.