diff --git a/src/Form/RoblibAlterSolrSettingsForm.php b/src/Form/RoblibAlterSolrSettingsForm.php
index 4b7a988..1750909 100644
--- a/src/Form/RoblibAlterSolrSettingsForm.php
+++ b/src/Form/RoblibAlterSolrSettingsForm.php
@@ -33,7 +33,7 @@ final class RoblibAlterSolrSettingsForm extends ConfigFormBase {
     $config = $this->config('roblib_alter_solr.settings');
     $solr_config = $this->config('search_api.index.default_solr_index');
     $solr_fields = $solr_config->get('field_settings');
-    $fields_options = [];
+    $fields_options = [' - ' => ' - '];
     foreach ($solr_fields as $name => $field) {
       $fields_options[$name] = $field['label'] . ' - ' . $name;
     }
@@ -183,6 +183,9 @@ final class RoblibAlterSolrSettingsForm extends ConfigFormBase {
     $user_input = $form_state->getUserInput();
     $unique_id = uniqid();
     $pairs = $user_input['pairs'] ?? [];
+    $pairs= array_filter($pairs, function ($item) {
+      return !empty($item['destination']);
+    });
     $pairs[$unique_id] = ['source' => '', 'destination' => ''];
     $form_state->set('pairs', $pairs);
     $form_state->setRebuild();
@@ -217,7 +220,7 @@ final class RoblibAlterSolrSettingsForm extends ConfigFormBase {
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $pairs = $form_state->getValue('pairs');
     $filtered_pairs= array_filter($pairs, function ($item) {
-      return !empty($item['destination']);
+      return !empty($item['destination']) && !isset($item['add']);
     });
     $normalize = $form_state->getValue('normalize');
     $this->config('roblib_alter_solr.settings')