Stationary rows in a drag and drop AdvancedDataGrid

Question

I have an AdvancedDataGrid that has drag-and-drop capabilities. The one caveat is that I don't want to be able to move the first or last rows in the grid. So if a user tries to drag one of these rows it is disallowed or if a user tries to drop another row into the first or last row it is disallowed. Does anyone know how I would do this?
Thanks

Answer 1

Found the answer
private function dragDropHandler(event:DragEvent):void{
                var dropTarget:AdvancedDataGrid = AdvancedDataGrid(event.currentTarget);
                var index:int = dropTarget.calculateDropIndex(event);
                if( index == 0 || index == event.currentTarget.dataProvider.length -1){
                    event.preventDefault();
                    event.stopImmediatePropagation();