* reviewed and fixed iframe height when HTML formatted textarea is used;

includes/core/class-fields.php

@@ -2805,7 +2805,7 @@ if ( ! class_exists( 'um\core\Fields' ) ) {
 							'media_buttons' => false,
 							'wpautop'       => false,
 							'editor_class'  => $this->get_class( $key, $data ),
-							'editor_height' => $data['height'],
+							'editor_height' => absint( $data['height'] ),
 							'tinymce'       => array(
 								'toolbar1' => 'formatselect,bullist,numlist,bold,italic,underline,forecolor,blockquote,hr,removeformat,link,unlink,undo,redo',
 								'toolbar2' => '',