diff --git a/plugins/Sitemap/sitemapaction.php b/plugins/Sitemap/sitemapaction.php
index bab04ed9d2..45edfccc51 100644
--- a/plugins/Sitemap/sitemapaction.php
+++ b/plugins/Sitemap/sitemapaction.php
@@ -87,4 +87,9 @@ class SitemapAction extends Action
     {
         return null;
     }
+
+    function isReadOnly()
+    {
+        return true;
+    }
 }