Turns icon_view into a drag source for automatic DND. Calling this method sets "reorderable" to FALSE. Since 2.8
Mask of allowed buttons to start drag
the table of targets that the drag will support
the bitmask of possible actions for a drag from this widget
See Implementation
Turns icon_view into a drag source for automatic DND. Calling this method sets "reorderable" to FALSE. Since 2.8