Restrict available LDAP servers.

You can view any available LDAP if you have access
to the root entity.

Otherwise, only the LDAP configured as the default
for the current entity is displayed.

inc/question.class.php

@@ -836,10 +836,17 @@ public function showForm($ID, $options = []) {
       if ($ldap_values === null) {
          $ldap_values = [];
       }
+      $current_entity = $_SESSION['glpiactive_entity'];
+      if ($current_entity == 0) {
+        $auth_ldap_condition = '';
+      } else {
+        $auth_ldap_condition = "glpi_authldaps.id in (select a.id from glpi_entities as e ,glpi_authldaps as a where a.id=e.authldaps_id and e.id=${current_entity})";
+      }
       Dropdown::show('AuthLDAP', [
          'name'      => 'ldap_auth',
+         'condition' => $auth_ldap_condition,
          'rand'      => $rand,
-         'value'     => (isset($ldap_values['ldap_auth'])) ? $ldap_values['ldap_auth'] : '',
+         'value'     => '',
          'on_change' => 'change_LDAP(this)',
       ]);
       echo '</div>';