diff --git a/bin/addons/base/rng/view.rng b/bin/addons/base/rng/view.rng
index 9c591723a9f..42aa180b8f3 100644
--- a/bin/addons/base/rng/view.rng
+++ b/bin/addons/base/rng/view.rng
@@ -248,6 +248,7 @@
             </rng:optional>
             <rng:optional><rng:attribute name="color"/></rng:optional>
             <rng:optional><rng:attribute name="date_delay"/></rng:optional>
+            <rng:optional><rng:attribute name="day_length"/></rng:optional>
             <rng:optional><rng:attribute name="date_start"/></rng:optional>
             <rng:optional><rng:attribute name="date_stop"/></rng:optional>
             <rng:optional><rng:attribute name="date_string"/></rng:optional>