Change globalChange to skip maps that are in the settings array but are...

Change globalChange to skip maps that are in the settings array but are missing from the actual page.

js/gmap.js

@@ -51,7 +51,10 @@
     globalChange: function (name, userdata) {
       for (var mapid in Drupal.settings.gmap) {
         if (Drupal.settings.gmap.hasOwnProperty(mapid)) {
-          maps[mapid].change(name, -1, userdata);
+          // Skip maps that are set up but not shown, etc.
+          if (maps[mapid]) {
+            maps[mapid].change(name, -1, userdata);
+          }
         }
       }
     },