diff --git a/src/wp-includes/widgets.php b/src/wp-includes/widgets.php
index 848249170a..b24b465503 100644
--- a/src/wp-includes/widgets.php
+++ b/src/wp-includes/widgets.php
@@ -616,9 +616,9 @@ function dynamic_sidebar( $index = 1 ) {
 	if ( is_int( $index ) ) {
 		$index = "sidebar-$index";
 	} else {
-		$sanitized_index = sanitize_title( $index );
+		$index = sanitize_title( $index );
 		foreach ( (array) $wp_registered_sidebars as $key => $value ) {
-			if ( sanitize_title( $value['name'] ) == $sanitized_index ) {
+			if ( sanitize_title( $value['name'] ) == $index ) {
 				$index = $key;
 				break;
 			}
diff --git a/tests/phpunit/tests/widgets.php b/tests/phpunit/tests/widgets.php
index b864408f62..0ac6d9258d 100644
--- a/tests/phpunit/tests/widgets.php
+++ b/tests/phpunit/tests/widgets.php
@@ -535,23 +535,6 @@ class Tests_Widgets extends WP_UnitTestCase {
 		$this->assertArrayNotHasKey( 2, $option_value );
 	}
 
-	/**
-	 * @ticket 23423
-	 */
-	function test_dynamic_sidebar_id_special_characters() {
-		wp_widgets_init();
-		register_sidebar( array(
-			'name' => 'Sidebar 2',
-			'id' => 'sidebar-2',
-		) );
-
-		ob_start();
-		$result = dynamic_sidebar( 'Sidebar 1' );
-		ob_end_clean();
-
-		$this->assertFalse( $result );
-	}
-
 	/**
 	 * @see wp_widget_control()
 	 */