diff --git a/edit/codemirror-default.js b/edit/codemirror-default.js
index 8576d9e0..94b156e7 100644
--- a/edit/codemirror-default.js
+++ b/edit/codemirror-default.js
@@ -105,6 +105,7 @@
   }
 
   Object.assign(CodeMirror.mimeModes['text/css'].propertyKeywords, {
+    'overflow-anchor': true,
     'overscroll-behavior': true,
   });
   Object.assign(CodeMirror.mimeModes['text/css'].colorKeywords, {
diff --git a/vendor-overwrites/csslint/parserlib.js b/vendor-overwrites/csslint/parserlib.js
index 7a92912f..263fb54d 100644
--- a/vendor-overwrites/csslint/parserlib.js
+++ b/vendor-overwrites/csslint/parserlib.js
@@ -508,6 +508,7 @@ self.parserlib = (() => {
     'outline-style':   '<border-style> | auto',
     'outline-width':   '<border-width>',
     'overflow':        '<overflow>{1,2}',
+    'overflow-anchor': 'auto | none',
     'overflow-block':  '<overflow>',
     'overflow-inline': '<overflow>',
     'overflow-style':  1,