diff --git a/admin/classes/output/theme_selector.php b/admin/classes/output/theme_selector.php
index 645e0fe497f..6fb69707929 100644
--- a/admin/classes/output/theme_selector.php
+++ b/admin/classes/output/theme_selector.php
@@ -55,7 +55,7 @@ class theme_selector implements renderable, templatable {
         // Theme data used to populate cards and modal.
         $data->themes = $this->themedata;
         // Reset theme caches button.
-        $reseturl = new moodle_url('admin/themeselector.php', ['sesskey' => sesskey(), 'reset' => 1]);
+        $reseturl = new moodle_url('/admin/themeselector.php', ['sesskey' => sesskey(), 'reset' => 1]);
         $resetbutton = new \single_button($reseturl, get_string('themeresetcaches', 'admin'), 'post',
             \single_button::BUTTON_SECONDARY);
         $data->resetbutton = $resetbutton->export_for_template($output);
diff --git a/theme/index.php b/theme/index.php
index 3bb694e3718..520b318db64 100644
--- a/theme/index.php
+++ b/theme/index.php
@@ -22,7 +22,6 @@
  */
 
 require_once(__DIR__ . '/../config.php');
-require_once($CFG->libdir . '/adminlib.php');
 
 // Theme selector has been moved to admin/themeselector.php.
 redirect (new moodle_url('/admin/themeselector.php'));