Issue #3513425 by andileco, nikathone: Selected column not getting saved on CSV Field Filter

src/Plugin/views/filter/ViewsCsvFilter.php

@@ -16,7 +16,6 @@ use Drupal\views_csv_source\Plugin\views\ColumnSelectorTrait;
 class ViewsCsvFilter extends FilterPluginBase {
 
   use ColumnSelectorTrait;
-  use ViewsCsvFilterTrait;
 
   /**
    * Exposed filter options.
@@ -30,7 +29,7 @@ class ViewsCsvFilter extends FilterPluginBase {
    */
   protected function defineOptions() {
     $options = parent::defineOptions();
-
+    $options['key'] = ['default' => ''];
     $options['expose']['contains']['required'] = ['default' => FALSE];
     $options['expose']['contains']['placeholder'] = ['default' => ''];
 

src/Plugin/views/filter/ViewsCsvFilterSelect.php

@@ -25,7 +25,7 @@ class ViewsCsvFilterSelect extends InOperator {
    */
   protected function defineOptions(): array {
     $options = parent::defineOptions();
-    $options['key']['default'] = '';
+    $options['key'] = ['default' => ''];
     $options['empty_cell_behavior']['default'] = 'none';
     $options['multi_value_cell_separator']['default'] = '';
     return $options;

src/Plugin/views/filter/ViewsCsvFilterTrait.php

-<?php
-
-namespace Drupal\views_csv_source\Plugin\views\filter;
-
-/**
- * Trait to add options to the filter handler.
- */
-trait ViewsCsvFilterTrait {
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function defineOptions(): array {
-    $options = parent::defineOptions();
-    $options['key']['default'] = '';
-    return $options;
-  }
-
-}