If set, specifies that all default actions should be taken.
If set for a widget, when a drop occurs, GTK+ will
will check if the drag matches this widget’s list of possible targets and
actions. If so, GTK+ will call gtk_drag_get_data() on behalf of the widget.
Whether or not the drop is successful, GTK+ will call gtk_drag_finish(). If
the action was a move, then if the drag was successful, then %TRUE will be
passed for the delete parameter to gtk_drag_finish().
If set for a widget, GTK+ will draw a highlight on this widget as long as a drag is over this widget and the widget drag format and action are acceptable.
If set for a widget, GTK+, during a drag over this widget will check if the drag matches this widget’s list of possible targets and actions. GTK+ will then call gdk_drag_status() as appropriate.
The #GtkDestDefaults enumeration specifies the various types of action that will be taken on behalf of the user for a drag destination site.