// assemble configuration
$gconf = (array)$extra;
- if (!is_null($sub) && is_array($this->config_raw['graph.'.$sub])) {
+ if (!is_null($sub) && array_key_exists('graph.'.$sub, $this->config_raw) && is_array($this->config_raw['graph.'.$sub])) {
$gconf = $gconf + $this->config_raw['graph.'.$sub];
}
$gconf = $gconf + (array)$this->config_graph;