diff --git a/lib/mixins/property-effects.html b/lib/mixins/property-effects.html
index 9dc5d3273e..2401f704fb 100644
--- a/lib/mixins/property-effects.html
+++ b/lib/mixins/property-effects.html
@@ -782,7 +782,7 @@
   const SQUOTE_STRING = '(?:' + '\'(?:[^\'\\\\]|\\\\.)*\'' + ')';
   const DQUOTE_STRING = '(?:' + '"(?:[^"\\\\]|\\\\.)*"' + ')';
   const STRING = '(?:' + SQUOTE_STRING + '|' + DQUOTE_STRING + ')';
-  const ARGUMENT = '(?:' + IDENT + '|' + NUMBER + '|' +  STRING + '\\s*' + ')';
+  const ARGUMENT = '(?:(' + IDENT + '|' + NUMBER + '|' +  STRING + ')\\s*' + ')';
   const ARGUMENTS = '(?:' + ARGUMENT + '(?:,\\s*' + ARGUMENT + ')*' + ')';
   const ARGUMENT_LIST = '(?:' + '\\(\\s*' +
                                 '(?:' + ARGUMENTS + '?' + ')' +
diff --git a/test/unit/property-effects-elements.html b/test/unit/property-effects-elements.html
index 0d9853cde0..2cb36bbd44 100644
--- a/test/unit/property-effects-elements.html
+++ b/test/unit/property-effects-elements.html
@@ -20,7 +20,7 @@
       computed-inline="{{computeInline(value,add, divide)}}"
       computed-inline2="{{computeInline(value, add,divide)}}"
       computed-inline3="{{computeInline(value, add,
-                                        divide)}}"
+                                        divide )}}"
       computedattribute$="{{computeInline(value, add,divide)}}"
       computedattribute2$="{{computeInline(
                                value, add, divide)}}"