diff --git a/views/bootstrap4/class.Bootstrap4.php b/views/bootstrap4/class.Bootstrap4.php
index 4278c3fe0..c15da71bf 100644
--- a/views/bootstrap4/class.Bootstrap4.php
+++ b/views/bootstrap4/class.Bootstrap4.php
@@ -1498,6 +1498,7 @@ $(document).ready(function() {
 				array(
 					'target' => 'docChooser'.$formid,
 					'remote' => "../out/out.DocumentChooser.php?form=".$formid."&folderid=".$this->params['dms']->getRootFolder()->getId(),
+					'class' => 'btn btn-secondary',
 					'title' => getMLText('document').'…'
 				));
 		$content .= "</div>\n";