rem: GtkWidget *item;
context: update_buttons (Totem *totem){	GtkWidget *item;	gboolean has_item;	/* Previous */	/* FIXME Need way to detect if DVD Title is at first chapter */	if (totem_playing_dvd (totem->mrl) != FALSE)	{		has_item = TRUE;	} else {		has_item = totem_playlist_has_previous_mrl (totem->playlist);	}	totem_main_set_sensitivity ("tmw_previous_button", has_item);	totem_main_set_sensitivity ("tcw_previous_button", has_item);	totem_main_set_sensitivity ("tmw_previous_chapter_menu_item", has_item);	totem_popup_set_sensitivity ("trcm_previous_chapter", has_item);	/* Next */	/* FIXME Need way to detect if DVD Title has no more chapters */	if (totem_playing_dvd (totem->mrl) != FALSE)	{		has_item = TRUE;	} else {		has_item = totem_playlist_has_next_mrl (totem->playlist);	}	totem_main_set_sensitivity ("tmw_next_button", has_item);	totem_main_set_sensitivity ("tcw_next_button", has_item);	totem_main_set_sensitivity ("tmw_next_chapter_menu_item", has_item);	totem_popup_set_sensitivity ("trcm_next_chapter", has_item);}