Adding the category for a custom entity reference field add other fields to the same category I have a custom entity reference field working well, but once I added the category to it the other entity reference fields appeared in the same category.

Here is my code:
/**
 * Plugin implementation of the 'region_token' field type.
 *
 * @FieldType(
 *   id = &quot;region_token&quot;,
 *   label = @Translation(&quot;Region Token&quot;),
 *   description = @Translation(&quot;Region custom token.&quot;),
 *   category = @Translation(&quot;Tokens&quot;),
 *   default_widget = &quot;region_select_widget&quot;,
 *   default_formatter = &quot;region_formatter&quot;,
 * )
 */
class RegionToken extends EntityReferenceItem {

Any idea about how to fix this?
I fixed the problem by adding the following code to the class
  /**
   * {@inheritdoc}
   */
  public static function getPreconfiguredOptions() {
    return [];
  }