From 859b6408b2475e93eee7d07e5a23ebf907772054 Mon Sep 17 00:00:00 2001
From: Dan Burzynski <contax@phrenetic.org>
Date: Thu, 24 Oct 2024 15:02:47 +0100
Subject: [PATCH] Possible fix for issue #1261

This is backwards compatible with 7.x and forwards compatible with 8.x
---
 core/Widget/Widget.php | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/core/Widget/Widget.php b/core/Widget/Widget.php
index 3533e3f6..67ec00c9 100644
--- a/core/Widget/Widget.php
+++ b/core/Widget/Widget.php
@@ -12,6 +12,7 @@
  */
 abstract class Widget extends \WP_Widget {
 	public static $registered_widget_ids = array();
+    private $registered_field_names = array();
 
 	/**
 	 * Widget Datastore
@@ -223,14 +224,12 @@ public function add_fields( $fields ) {
 	 * @return boolean
 	 */
 	public function register_field_name( $name ) {
-		static $registered_field_names = array();
-
-		if ( in_array( $name, $registered_field_names ) ) {
+		if ( in_array( $name, $this->registered_field_names ) ) {
 			Incorrect_Syntax_Exception::raise( 'Field name "' . $name . '" already registered' );
 			return false;
 		}
 
-		$registered_field_names[] = $name;
+		$this->registered_field_names[] = $name;
 		return true;
 	}