diff --git a/code/hooks.js b/code/hooks.js
index 44c6826c..26c4bb9d 100644
--- a/code/hooks.js
+++ b/code/hooks.js
@@ -110,6 +110,10 @@ window.removeHook = function(event, callback) {
   if (typeof callback !== 'function') throw('Callback must be a function.');
 
   if (_hooks[event]) {
-    _hooks[event].splice(_hooks[event].indexOf(callback), 1);
+    var index = _hooks[event].indexOf(callback);
+    if(index == -1)
+      console.warn('Callback wasn\'t registered for this event.');
+    else
+      _hooks[event].splice(index, 1);
   }
 }