--- /usr/share/ganglia-webfrontend/cluster_view.php.orig        2014-04-04 12:20:44.000000000 +0200
+++ /usr/share/ganglia-webfrontend/cluster_view.php     2019-03-28 09:21:24.655552408 +0100
@@ -23,7 +23,7 @@
 }
 
 function get_picker_metrics($metrics, $reports, $gweb_root, $graph_engine) {
-  $context_metrics = "";
+  $context_metrics = array();
   if (count($metrics)) {
     foreach ($metrics as $host_metrics) {
       foreach ($host_metrics as $metric_name => $metric_value) {