The dragging clue element is shown before the actual dragging of the element in the Grid is initiated (immediately after the item is clicked). The problem is reproducible in Chrome.
Comment: The problem is not reproducible in the following TreeView demo:
Steps to reproduce:
1. Open http://demos.telerik.com/aspnet-ajax/grid/examples/columns-rows/rows/drag-and-drop/defaultcs.aspx
2. Click over an item (just mouse-down, without moving the mouse nor full click)
Result: The dragging clue is shown without actual moving of the mouse pointer