diff --git a/lib/Models/CatalogItem.js b/lib/Models/CatalogItem.js
index <HASH>..<HASH> 100644
--- a/lib/Models/CatalogItem.js
+++ b/lib/Models/CatalogItem.js
@@ -360,7 +360,7 @@ var CatalogItem = function(terria) {
     // that it depends on and update the subscription (watcher) on the terria.clock when the state changes.
     knockout.defineProperty(this, '_mirroringTerriaClock', {
         get: function() {
-          return this.isEnabled && !this.useOwnClock && defined(this.clock);
+          return this.isEnabled && this.isShown && !this.useOwnClock && defined(this.clock);
         }
     });
[#<I>] CatalogItem: Add isShown to the _mirroringTerriaClock property.