Called when user starts dragging a draggable column.
onColumnDragStart = function(event)
This event is triggered when user starts dragging a draggable column. It will receive one argument
event
that will contain information what column was dragged.
You can add event listener during the object creation:
or after the object has been created:
Your event listener can be executed before or after the event has been processed. You can also cancel
the default behavior. See
Events page in utilities.