gboolean gtk_tree_drag_source_row_draggable ( GtkTreeDragSource* drag_source, GtkTreePath* path )
GtkTreeDragSource whether a particular row can be used as
the source of a DND operation. If the source doesn’t implement
this interface, the row is assumed draggable.
Row on which user is initiating a drag.
|The data is owned by the caller of the function.|