Issue #601794 by stuckagain, ezra-g : fixed conflict with core filter settings.

url_replace_filter.module

@@ -64,13 +64,13 @@ function _url_replace_filter_process($text, $format) {
  */
 function _url_replace_filter_settings($format) {
   $empty = 0;
-  $form['#tree'] = TRUE;
   $form['url_replace_filter_'. $format] = array(
     '#type' => 'fieldset',
     '#title' => t('URL Replace Filter'),
     '#collapsible' => TRUE,
     '#collapsed' => FALSE,
     '#theme' => 'url_replace_filter_settings_form',
+    '#tree' => TRUE,
   );
   $settings = _url_replace_filter_get_settings($format);
   foreach ($settings as $index => $setting) {