Hi Mr Dam,
We have created a Joomla 4 test site from our Joomla 3 production site. The Edocman buttons such as VIEW EDIT are different in Joomla 4. They are white in appearance and difficult to read unless moused over. If I modify bootstrap.php in helper for bootstrap 5 $classMaps to 'btn' => 'btn btn-primary' instead of btn btn-secondary , it fixes the problem.