- struct spreadlevel_plot_chart *sl = xzalloc (sizeof *sl);
- chart_item_init (&sl->chart_item, &spreadlevel_plot_chart_class, label);
+ struct spreadlevel_plot_chart *sl = XZALLOC (struct spreadlevel_plot_chart);
+ chart_init (&sl->chart, &spreadlevel_plot_chart_class, label);