rem: gtk_widget_set_sensitive (item, gtk_playlist_has_previous_mrl (totem->playlist));
add: gtk_widget_set_sensitive (item, has_item); item = glade_xml_get_widget (totem->xml, "previous_stream1"); gtk_widget_set_sensitive (item, has_item);
context: update_buttons (Totem *totem){	GtkWidget *item;	/* Previous */	item = glade_xml_get_widget (totem->xml, "previous_button");	gtk_widget_set_sensitive (item,			gtk_playlist_has_previous_mrl (totem->playlist));	/* Next */	item = glade_xml_get_widget (totem->xml, "next_button");	gtk_widget_set_sensitive (item,			gtk_playlist_has_next_mrl (totem->playlist));}