diff --git a/wp-includes/class-wp-customize-setting.php b/wp-includes/class-wp-customize-setting.php
index e37bb65de8..64693a2595 100644
--- a/wp-includes/class-wp-customize-setting.php
+++ b/wp-includes/class-wp-customize-setting.php
@@ -129,11 +129,11 @@ class WP_Customize_Setting {
 	 * @since 4.2.0
 	 * @access public
 	 *
-	 * @return bool If preview() has been called.
+	 * @return bool|void If preview() has been called.
 	 */
 	public function is_current_blog_previewed() {
 		if ( ! isset( $this->_previewed_blog_id ) ) {
-			return false;
+			return;
 		}
 		return ( get_current_blog_id() === $this->_previewed_blog_id );
 	}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index df36690f43..bc49602267 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.3-alpha-32765';
+$wp_version = '4.3-alpha-32766';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.