diff --git plugins/views_plugin_display.inc plugins/views_plugin_display.inc
index db8ccb9..db4c5ad 100644
--- plugins/views_plugin_display.inc
+++ plugins/views_plugin_display.inc
@@ -1059,7 +1059,7 @@ class views_plugin_display extends views_plugin {
         $form['#title'] .= t('The machine name of this display');
         $form['display_id'] = array(
           '#type' => 'textfield',
-          '#description' => t('This is machine name of the display.'),
+          '#description' => t('This is machine name of the display. It must contain only alphanumeric characters and underscores.'),
           '#default_value' => !empty($this->display->new_id) ? $this->display->new_id : $this->display->id,
           '#required' => TRUE,
           '#size' => 64,
@@ -1694,6 +1694,9 @@ class views_plugin_display extends views_plugin {
             if ($id != $this->view->current_display && ($form_state['values']['display_id'] == $id || $form_state['values']['display_id'] == $display->new_id)) {
               form_error($form['display_id'], t('Display id should be unique.'));
             }
+            if (preg_match('/[^a-zA-Z0-9_]/', $form_state['values']['display_id'])) {
+              form_error($form['display_id'], t('Display name must be alphanumeric or underscores only.'));
+            }
           }
         }
         break;