nsIDOMNSDataTransfer_MOZILLA_1_9_1 in Firefox 3.5

 Sets the drag cursor state. Primarily used to control the cursor during
 tab drags, but could be expanded to other uses. XXX Currently implemented
 on Win32 only.

 Possible values:
  auto - use default system behavior.
  default - set the cursor to an arrow during the drag operation.

 Values other than 'default' are indentical to setting mozCursor to
 'auto'.