diff --git a/src/js/static-net-filtering.js b/src/js/static-net-filtering.js
index 5add2e634..578480a0b 100644
--- a/src/js/static-net-filtering.js
+++ b/src/js/static-net-filtering.js
@@ -4505,6 +4505,7 @@ FilterContainer.prototype.dnrFromCompiled = function(op, context, ...args) {
             }
             break;
         default:
+            dnrAddRuleError(rule, `Unsupported modifier ${rule.__modifierType}`);
             break;
         }
     }