Index: class-wp-customize-manager.php
--- class-wp-customize-manager.php BASE
+++ class-wp-customize-manager.php LOCAL
@@ -462,6 +462,8 @@
 	 * Check if customize query variable exist. Init filters to filter the current theme.
 	 *
 	 * @since 3.4.0
+	 *
+	 * @global string $pagenow
 	 */
 	public function setup_theme() {
 		global $pagenow;