diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index bbd9bc4554..9913a80a70 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -4632,7 +4632,7 @@ function page_header($page_title = '', $display_online_list = true, $item_id = 0
 		foreach ($_EXTRA_URL as $url_param)
 		{
 			$url_param = explode('=', $url_param, 2);
-			$s_hidden_fields[$url_param[0]] = $url_param[1];
+			$s_search_hidden_fields[$url_param[0]] = $url_param[1];
 		}
 	}
 
diff --git a/phpBB/viewforum.php b/phpBB/viewforum.php
index 76dcfe22a3..2d91581cf4 100644
--- a/phpBB/viewforum.php
+++ b/phpBB/viewforum.php
@@ -282,7 +282,7 @@ if (!empty($_EXTRA_URL))
 	foreach ($_EXTRA_URL as $url_param)
 	{
 		$url_param = explode('=', $url_param, 2);
-		$s_hidden_fields[$url_param[0]] = $url_param[1];
+		$s_search_hidden_fields[$url_param[0]] = $url_param[1];
 	}
 }
 
diff --git a/phpBB/viewtopic.php b/phpBB/viewtopic.php
index cb6edf8423..7cb6df3660 100644
--- a/phpBB/viewtopic.php
+++ b/phpBB/viewtopic.php
@@ -567,7 +567,7 @@ if (!empty($_EXTRA_URL))
 	foreach ($_EXTRA_URL as $url_param)
 	{
 		$url_param = explode('=', $url_param, 2);
-		$s_hidden_fields[$url_param[0]] = $url_param[1];
+		$s_search_hidden_fields[$url_param[0]] = $url_param[1];
 	}
 }