Merge pull request #56 from NightJar/patch-1

Avoid fatal errors when trying to edit in the CMS

code/extensions/SiteTreeContentReview.php

@@ -454,6 +454,10 @@ class SiteTreeContentReview extends DataExtension implements PermissionProvider
 
         $options = $this->getOptions();
 
+        if (!$options || !$options->hasExtension($this->class)) {
+            return false;
+        }
+
         if ($options->OwnerGroups()->count() == 0 && $options->OwnerUsers()->count() == 0) {
             return false;
         }