fix(MassiveAction): fix incompatibility with multiple dropdowns

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [UNRELEASE]
 
+- Fix incompatibility of `multiple` dropdowns with `massiveaction`
+
 ## [1.21.22] - 2025-05-28
 
 ### Fixed

inc/container.class.php

@@ -1833,6 +1833,11 @@ private static function populateData($c_id, CommonDBTM $item)
                         ) { //multi dropdown is empty or has been emptied
                             $data[$multiple_key] = [];
                             $has_fields          = true;
+                        } elseif (isset($_REQUEST['massiveaction'])) { // called from massiveaction
+                            if (isset($_POST[$multiple_key])) {
+                                $data[$multiple_key] = $_POST[$multiple_key];
+                                $has_fields          = true;
+                            }
                         }
                     }