diff --git a/includes/simplenews.admin.inc b/includes/simplenews.admin.inc
index 7120bdc..9ec2160 100644
--- a/includes/simplenews.admin.inc
+++ b/includes/simplenews.admin.inc
@@ -507,6 +507,21 @@ function simplenews_admin_category_form($form, &$form_state, $edit = array()) {
       '#markup' => t('Newsletter emails will be sent in %format format.', array('%format' => $edit['format'])),
     );
   }
+  // Type of hyperlinks setting.
+  $form['email']['hyperlinks'] = array(
+    '#type' => 'radios',
+    '#title' => t('Hyperlink conversion'),
+    '#description' => t('Determine how the conversion to text is performed.'),
+    '#options' => array(t('Append hyperlinks as a numbered reference list'), t('Display hyperlinks inline with the text')),
+    '#default_value' => $edit['hyperlinks'],
+    '#states' => array(
+      'visible' => array(
+        ':input[name="format"]' => array(
+          'value' => 'plain',
+        ),
+      ),
+    ),
+  );
 
   $form['email']['priority'] = array(
     '#type' => 'select',
@@ -573,20 +588,6 @@ function simplenews_admin_category_form($form, &$form_state, $edit = array()) {
     '#default_value' => $edit['from_address'],
   );
 
-  // Type of hyperlinks
-  $form['simplenews_hyperlinks'] = array(
-    '#type' => 'fieldset',
-    '#title' => t('HTML to text conversion'),
-    '#collapsible' => FALSE,
-    '#description' => t('When your newsletter is sent as plain text, these options will determine how the conversion to text is performed.'),
-  );
-  $form['simplenews_hyperlinks']['hyperlinks'] = array(
-    '#type' => 'radios',
-    '#title' => t('Hyperlink conversion'),
-    '#options' => array(t('Append hyperlinks as a numbered reference list'), t('Display hyperlinks inline with the text')),
-    '#default_value' => $edit['hyperlinks'],
-  );
-
   $form['actions'] = array('#type' => 'actions');
   $form['actions']['submit'] = array(
     '#type' => 'submit',