diff --git a/lib/src/generator/html_generator.dart b/lib/src/generator/html_generator.dart
index b55b966f7e..4db154a715 100644
--- a/lib/src/generator/html_generator.dart
+++ b/lib/src/generator/html_generator.dart
@@ -70,7 +70,8 @@ class HtmlGeneratorBackend extends GeneratorBackend {
     var data = ExtensionTypeTemplateData(
         options, packageGraph, library, extensionType);
     var sidebarContent = templates.renderSidebarForContainer(data);
-    write(writer, extensionType.sidebarPath, data, sidebarContent);
+    write(writer, extensionType.sidebarPath, data, sidebarContent,
+        isSidebar: true);
     runtimeStats.incrementAccumulator('writtenSidebarFileCount');
   }
 
diff --git a/test/templates/extension_type_test.dart b/test/templates/extension_type_test.dart
index 05448044ac..928c860eb1 100644
--- a/test/templates/extension_type_test.dart
+++ b/test/templates/extension_type_test.dart
@@ -361,10 +361,10 @@ extension type One(int it) {
       htmlLines,
       containsAllInOrder([
         matches(
-          '<a href="../lib/One-extension-type.html#instance-methods">'
+          '<a href="lib/One-extension-type.html#instance-methods">'
           'Methods</a>',
         ),
-        matches('<a href="../lib/One/m1.html">m1</a>'),
+        matches('<a href="lib/One/m1.html">m1</a>'),
       ]),
     );
   }
@@ -381,8 +381,8 @@ extension type One(int it) {
       htmlLines,
       containsAllInOrder([
         matches(
-            '<a href="../lib/One-extension-type.html#operators">Operators</a>'),
-        matches('<a href="../lib/One/operator_greater.html">operator ></a>'),
+            '<a href="lib/One-extension-type.html#operators">Operators</a>'),
+        matches('<a href="lib/One/operator_greater.html">operator ></a>'),
       ]),
     );
   }
@@ -402,10 +402,10 @@ extension type One(int it) {
     expect(
       htmlLines,
       containsAllInOrder([
-        matches('<a href="../lib/One-extension-type.html#static-properties">'
+        matches('<a href="lib/One-extension-type.html#static-properties">'
             'Static properties</a>'),
-        matches('<a href="../lib/One/gs1.html">gs1</a>'),
-        matches('<a href="../lib/One/sf1.html">sf1</a>'),
+        matches('<a href="lib/One/gs1.html">gs1</a>'),
+        matches('<a href="lib/One/sf1.html">sf1</a>'),
       ]),
     );
   }
@@ -421,9 +421,9 @@ extension type One(int it) {
     expect(
       htmlLines,
       containsAllInOrder([
-        matches('<a href="../lib/One-extension-type.html#static-methods">'
+        matches('<a href="lib/One-extension-type.html#static-methods">'
             'Static methods</a>'),
-        matches('<a href="../lib/One/s1.html">s1</a>'),
+        matches('<a href="lib/One/s1.html">s1</a>'),
       ]),
     );
   }