diff --git a/src/wp-includes/class-wp-customize-manager.php b/src/wp-includes/class-wp-customize-manager.php
index 556bc60d8b..43859f1dda 100644
--- a/src/wp-includes/class-wp-customize-manager.php
+++ b/src/wp-includes/class-wp-customize-manager.php
@@ -1175,7 +1175,7 @@ final class WP_Customize_Manager {
 		) );
 
 		if ( $menus ) {
-			$choices = array( 0 => __( '— Select —' ) );
+			$choices = array( '' => __( '— Select —' ) );
 			foreach ( $menus as $menu ) {
 				$choices[ $menu->term_id ] = wp_html_excerpt( $menu->name, 40, '…' );
 			}