diff --git a/htmlmail.admin.inc b/htmlmail.admin.inc
index fcfea09..3bd0b8a 100644
--- a/htmlmail.admin.inc
+++ b/htmlmail.admin.inc
@@ -236,7 +236,9 @@ function htmlmail_test_form($form_values = NULL) {
       ),
     )
   );
-  $defaults['body']['format'] = filter_fallback_format();
+  if (empty($defaults['body']['format'])) {
+    $defaults['body']['format'] = filter_fallback_format();
+  }
   $form['to'] = array(
     '#type' => 'textfield',
     '#title' => t('To'),