8.1.1 TreeGrid dataTranfer.types is empty at client end

Chrome 60.0.3112.78
I am trying to migrate some code from vaadin 7.7 to 8.1 and now I am trying to set some client side acceptance critera for drops in treeGrid. I am using below code. You can use any object in place of TOC.

TreeGrid tocTree = new TreeGrid();
tocTree.addColumn(tocVO → tocVO.getCaption())
.setStyleGenerator(tocVO → tocVO.getName());

TreeGridDragSource dragSource = new TreeGridDragSource<>(tocTree);
dragSource.setDragDataGenerator(“tocItemType”, tocVO → tocVo.getName());
dragSource.addGridDragStartListener((GridDragStartListener) event → {
Set draggedItems = event.getDraggedItems();
if (draggedItems.size() > 0) {
TOC draggedItem = draggedItems.iterator().next();
dragSource.setDragData(draggedItem);//set only one node

    TreeGridDropTarget<TOC> dropTarget = new TreeGridDropTarget<>(tocTree, DropMode.ON_TOP_OR_BETWEEN);
                    + "if (event.dataTransfer.types.length > 0) {"
                    +      "console.log('SOME TYPE FOUND');"
                    +      "if(event.dataTransfer.types['tocItemType']

+ “return true;”
+ “}”
+ “}”
// Otherwise cancel the event
+ “return false;”
[/code]Now I am setting some data in line 10. But I am not getting anything in event.dataTransfer.types. I have tried several combinations in script and dataGenerators/ manually setting the data etc. but to no avail. Is there anything which I am missing here to create a client side accept criteria.


Just to inform, the data is not accessible in chrome as dataTransfer object is in protected mode in dragover in Chrome whereas in FF dataTransfer object can be accessed in dragover event. This is browser specific.