diff --git a/views/bootstrap4/class.Bootstrap4.php b/views/bootstrap4/class.Bootstrap4.php
index c15da71bf..7f81d11a2 100644
--- a/views/bootstrap4/class.Bootstrap4.php
+++ b/views/bootstrap4/class.Bootstrap4.php
@@ -1565,6 +1565,7 @@ function folderSelected<?php echo $formid ?>(id, name) {
 				array(
 					'target' => 'folderChooser'.$formid,
 					'remote' => "../out/out.FolderChooser.php?form=".$formid."&mode=".$accessMode."&exclude=".$exclude,
+					'class' => 'btn btn-secondary',
 					'title' => getMLText('folder').'…'
 				));
 		}
@@ -1639,6 +1640,7 @@ $(document).ready(function() {
 			array(
 				'target' => 'keywordChooser',
 				'remote' => "../out/out.KeywordChooser.php?target=".$formName,
+				'class' => 'btn btn-secondary',
 				'title' => getMLText('keywords').'…'
 			));
 		$content .= '
@@ -1902,6 +1904,7 @@ $(document).ready(function() {
 			array(
 				'target' => 'dropfolderChooser',
 				'remote' => "../out/out.DropFolderChooser.php?form=".$formName."&dropfolderfile=".urlencode($dropfolderfile)."&showfolders=".$showfolders,
+				'class' => 'btn btn-secondary',
 				'title' => ($showfolders ? getMLText("choose_target_folder"): getMLText("choose_target_file")).'…'
 			));
 		$content .= "</div>\n";