AdvancedDataGrid Drag Drop Error

Question

I'm running into an issue where AdvancedDataGrid is not
accepting drag and drop from controls that do not implement
dataprovider in HierarchicalData format. If i change the ADG's
dataprovider to a flat arraycollection then it will be able to
receive drag drop from other controls. I've tried overridding the
drag events to accept the drops but that still does not work. What
key info am i missing to get a HierarchicalData format ADG to
accept drag drop items from other controls?

Answer 1

5 years late, but I just ran across the same issue and this is what worked for me:
protected function dragOverHandler(event:DragEvent):void {
    event.preventDefault();
    DragManager.showFeedback(DragManager.COPY);
    AdvancedDataGrid(event.currentTarget).showDropFeedback(event);