diff --git a/src/js/static-ext-filtering.js b/src/js/static-ext-filtering.js
index 8dadd9673..f9a098b07 100644
--- a/src/js/static-ext-filtering.js
+++ b/src/js/static-ext-filtering.js
@@ -54,7 +54,7 @@
     var µb = µBlock,
         reHostnameSeparator = /\s*,\s*/,
         reHasUnicode = /[^\x00-\x7F]/,
-        reParseRegexLiteral = /^\/(.+)\/([im]+)?$/,
+        reParseRegexLiteral = /^\/(.+)\/([imu]+)?$/,
         emptyArray = [],
         parsed = {
             hostnames: [],