Ticket #21515: 21515.patch

wp-includes/class-wp-customize-control.php

@@ -750 +750 @@
          */
         public function prepare_control() {
                 global $custom_image_header;
+                if( empty( $custom_image_header ) )
+                        return parent::prepare_control();
 
                 // Process default headers and uploaded headers.
                 $custom_image_header->process_default_headers();