fixes #4275

Closes #4275

Merge request studip/studip!3093

app/views/course/dates/_date_row.php

@@ -15,7 +15,7 @@ $dialog_url = $show_raumzeit
             ? $controller->url_for('course/dates/details/' . $date->id)
             : $controller->url_for('course/dates/singledate/' . $date->id);
 ?>
-<tr id="date_<?= $date->id ?>" <? if ($is_next_date) echo 'class="nextdate" title="' . _('Der nächste Termin') . '"'; ?> data-termin-id="<?= htmlReady($date->id) ?>">
+<tr id="date_<?= $date->id ?>" <? if (!empty($is_next_date)) echo 'class="nextdate" title="' . _('Der nächste Termin') . '"'; ?> data-termin-id="<?= htmlReady($date->id) ?>">
     <td data-sort-value="<?= htmlReady($date->date) ?>" class="date_name">
         <a href="<?= $dialog_url ?>" data-dialog>
             <?= Icon::create($icon)->asImg(['class' => 'text-bottom']) ?>