GtkToolItem::set_use_drag_window

void set_use_drag_window(bool use_drag_window);

Sets whether toolitem has a drag window. When true the toolitem can be used as a drag source through drag_source_set. When the tool item has a drag window it will intercept all events, even those that would otherwise be sent to a child of toolitem.

See also: get_use_drag_window()