When nodes in a treegrid are rearranged by drag and drop:
This is done by:
dropModel.diHelperspecifies the displayed columns in the draggable helper.
dragModel.isDraggableis implemented to exclude summary rows and root nodes.
dropModel.isDroppableis implemented to exclude summary rows, ancestor rows of dropped rows and if dragged and dropped over rows are same.
dropModel.dropmoves the rows from old parent to new parent. You can override it to do custom action upon drop of rows.
First of all mutiple row selection is turned on or checkbox selection is turned on.
dragModel.dragNodes method is implemented as in this example to return array of selected or checked rows.