User deletion page freezes when user count is large due to dropdown user list

[topgsmir]

When deleting a user from the admin panel (/wp-admin/users.php?action=delete), WordPress shows a dropdown list to reassign the user’s posts to another user.

If the site has a large number of users (for example, more than 10,000), this dropdown is rendered using a <select> element that loads all users at once. This causes the browser to freeze or become unresponsive.

Steps to reproduce:

Create a WordPress site with many users (e.g., import 10,000+ users).

Go to “Users → All Users”.

Try deleting any user.

On the deletion confirmation page, notice the “Attribute all content to” dropdown tries to load all users.

The page becomes slow or freezes.

Expected behavior:
The user selection dropdown should use AJAX search or pagination to dynamically load users instead of loading all at once.

Actual behavior:
The dropdown renders all users in one go, causing performance issues and sometimes freezing the browser.

Environment:

PHP Version: 8.1+

Browser: All major browsers affected

Database: MySQL / MariaDB

Possible Solution:
Use an AJAX-powered user search field (like wp_dropdown_users() replacement) similar to the “Author” selection in post editing.

[westonruter]

Thank you. This is a known issue. See #19867.

Related: #56129 proposes adding an author dropdown for Quick Edit, but it is not feasible because the dropdown is not scalable at present.