}
static void panels_forall(GtkContainer *container, gboolean include_internals,                           GtkCallback callback, gpointer callback_data){    Panels *panels;    GtkWidget *child;    GList *children;    g_return_if_fail(container != NULL);    g_return_if_fail(IS_PANELS(container));    g_return_if_fail(callback != NULL);    panels = PANELS(container);    for (children = panels->children;         children && (child = children->data);         children = children->next)	if (child)	    callback(child, callback_data);}