Ticket #19091: 19091.patch

wp-includes/widgets.php

@@ -296 +296 @@
                 if ( !is_array($settings) )
                         $settings = array();
 
-                if ( !array_key_exists('_multiwidget', $settings) ) {
+                if ( !empty($settings) && !array_key_exists('_multiwidget', $settings) ) {
                         // old format, convert if single widget
                         $settings = wp_convert_widget_settings($this->id_base, $this->option_name, $settings);
                 }