+ context = gtk_widget_get_style_context (widget);
+
+ state = gtk_widget_get_state_flags (widget);
+ gtk_style_context_save (context);
+ gtk_style_context_add_class (context, GTK_STYLE_CLASS_TROUGH);
+ gtk_style_context_get_margin (context, state, &trough_margin);
+ gtk_style_context_restore (context);