diff --git a/edit/codemirror-default.js b/edit/codemirror-default.js
index 0912f445..74fc2942 100644
--- a/edit/codemirror-default.js
+++ b/edit/codemirror-default.js
@@ -371,8 +371,11 @@ CodeMirror.hint && (() => {
     }
 
     // USO vars in usercss mode editor
-    const list = Object.keys(editor.getStyle().usercssData.vars)
-      .filter(name => name.startsWith(leftPart));
+    const vars = editor.getStyle().usercssData.vars;
+    const list = vars ?
+      Object.keys(editor.getStyle().usercssData.vars)
+        .filter(name => name.startsWith(leftPart)) :
+      [];
     return {
       list,
       from: {line, ch: prev},
diff --git a/manage/manage.js b/manage/manage.js
index 01b005f8..e9a8dd56 100644
--- a/manage/manage.js
+++ b/manage/manage.js
@@ -195,7 +195,7 @@ function createStyleElement({style, name}) {
     };
   }
   const parts = createStyleElement.parts;
-  const configurable = style.usercssData && Object.keys(style.usercssData.vars).length > 0;
+  const configurable = style.usercssData && style.usercssData.vars && Object.keys(style.usercssData.vars).length > 0;
   parts.checker.checked = style.enabled;
   parts.nameLink.textContent = tWordBreak(style.name);
   parts.nameLink.href = parts.editLink.href = parts.editHrefBase + style.id;