fixes #4026

Closes #4026

Merge request studip/studip!2881

app/views/course/wizard/steps/studyareas/_assigned_node.php

 <li class="sem-tree-assigned-<?= $element['id'] ?>">
     <?= htmlReady($element['name']) ?>
-    <?php if (!$values['locked'] && $element['assignable'] && in_array($element['id'], $studyareas ?: [])) : ?>
-        <?= Icon::create('trash', 'clickable')->asInput(["name" => 'unassign['.$element['id'].']', "onclick" => "return STUDIP.CourseWizard.unassignNode('".$element['id']."')"]) ?>
-    <input type="hidden" name="studyareas[]" value="<?= $element['id'] ?>"/>
+    <?php if (empty($values['locked']) && $element['assignable'] && in_array($element['id'], $studyareas ?: [])) : ?>
+        <?= Icon::create('trash')->asInput(["name" => 'unassign['.$element['id'].']', "onclick" => "return STUDIP.CourseWizard.unassignNode('".$element['id']."')"]) ?>
+    <input type="hidden" name="studyareas[]" value="<?= htmlReady($element['id']) ?>"/>
     <?php endif ?>
     <ul>
         <?php foreach ($element['children'] as $c) : ?>
         <?= $this->render_partial('studyareas/_assigned_node', ['element' => $c]) ?>
         <?php endforeach ?>
     </ul>
-</li>
+</li>
\ No newline at end of file

lib/models/Lvgruppe.php

@@ -232,7 +232,7 @@ class Lvgruppe extends ModuleManagementModelTreeItem
      *
      * @param string $term The search term.
      * @param array|string $filter An array with filter options or a where part.
-     * @return object A SimpleORMapCollection of LV-Gruppen.
+     * @return SimpleORMapCollection A SimpleORMapCollection of LV-Gruppen.
      */
     public static function findBySearchTerm($term, $filter = null)
     {
@@ -271,7 +271,7 @@ class Lvgruppe extends ModuleManagementModelTreeItem
      * Retrieves all LV-Gruppen related to the Modulteil with given id.
      *
      * @param string $modulteil_id The id of a Modulteil.
-     * @return object A SimpleORMapCollection of LV-Gruppen.
+     * @return SimpleORMapCollection A SimpleORMapCollection of LV-Gruppen.
      */
     public static function findByModulteil($modulteil_id)
     {
@@ -286,7 +286,7 @@ class Lvgruppe extends ModuleManagementModelTreeItem
      * Retrieves all LV-Gruppen related to the course with given id.
      *
      * @param string $seminar_id The id of a course.
-     * @return object A SimpleORMapCollection of LV-Gruppen.
+     * @return SimpleORMapCollection A SimpleORMapCollection of LV-Gruppen.
      */
     public static function findBySeminar($seminar_id)
     {
@@ -339,7 +339,7 @@ class Lvgruppe extends ModuleManagementModelTreeItem
     /**
      * Assigns the given course to the given LvGruppen.
      *
-     * @param array Array of ids
+     * @param string $seminar_id Array of ids
      * @return int The number of assigned LvGruppen.
      */
     public static function setLvgruppen($seminar_id, $lvgruppen_ids)
@@ -347,9 +347,13 @@ class Lvgruppe extends ModuleManagementModelTreeItem
         $old = Lvgruppe::findBySeminar($seminar_id);
         $removed = array_diff($old->pluck('id'), $lvgruppen_ids);
         $added = array_diff($lvgruppen_ids, $old->pluck('id'));
+
+        $count_removed = 0;
         foreach ($removed as $one) {
             $count_removed += $old->findOneBy('id', $one)->removeSeminar($seminar_id);
         }
+
+        $count_added = 0;
         foreach ($added as $one) {
             $count_added += Lvgruppe::get($one)->addSeminar($seminar_id);
         }