--- ImceFileField.php.orig	2020-06-11 16:33:06.000000000 +0800
+++ ImceFileField.php	2020-06-11 16:36:18.000000000 +0800
@@ -5,11 +5,12 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Field\WidgetInterface;
 use Drupal\Core\Url;
+use Drupal\Core\Security\TrustedCallbackInterface;
 
 /**
  * Defines methods for integrating Imce into file field widgets.
  */
-class ImceFileField {
+class ImceFileField implements TrustedCallbackInterface {
 
   /**
    * Returns a list of supported widgets.
@@ -79,6 +80,13 @@
   }
 
   /**
+   * {@inheritdoc}
+   */
+  public static function trustedCallbacks() {
+    return ['preRenderWidget'];
+  }
+
+  /**
    * Pre-renders widget form.
    */
   public static function preRenderWidget($element) {