diff --git a/tildes/static/js/behaviors/hide-sidebar-no-preventdefault.js b/tildes/static/js/behaviors/hide-sidebar-no-preventdefault.js
new file mode 100644
index 0000000..775051b
--- /dev/null
+++ b/tildes/static/js/behaviors/hide-sidebar-no-preventdefault.js
@@ -0,0 +1,8 @@
+// Copyright (c) 2018 Tildes contributors <code@tildes.net>
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+$.onmount('[data-js-hide-sidebar-no-preventdefault]', function() {
+    $(this).on('click', function(event) {
+        $('#sidebar').removeClass('is-sidebar-displayed');
+    });
+});
diff --git a/tildes/tildes/templates/topic.jinja2 b/tildes/tildes/templates/topic.jinja2
index d148ff0..a6562f9 100644
--- a/tildes/tildes/templates/topic.jinja2
+++ b/tildes/tildes/templates/topic.jinja2
@@ -261,7 +261,7 @@
 
     <dt>Last comment posted</dt>
     <dd>
-      <a href="{{ comments.most_recent_comment.permalink }}">
+      <a href="{{ comments.most_recent_comment.permalink }}" data-js-hide-sidebar-no-preventdefault>
         {{ time_ago(topic.last_activity_time) }}
       </a>
     </dd>