Event was introduced in dhtmlxScheduler 2.1 and not applicable to older versions.

Parameters:

• id of event;
• drag mode - can be “move”,”resize”,”create”
• native event object.

  scheduler.attachEvent("onBeforeDrag", function (event_id, mode, native_event_object){
       //any custom logic here
       return true;
  });

Event called when mouse pressed inside a scheduler on the element, which can be dragged.

For “create” mode, id value is not provided ( new event is not created yet )

Event is blockable, returning false will block related action.