diff --git a/src/Plugin/CKEditorPlugin/MathJaxPlugin.php b/src/Plugin/CKEditorPlugin/MathJaxPlugin.php
index 03a61afae6af60733f42465e352894285ebb00f5..c97d3663c1346e9c7d908b96ff2dddfb39037cfe 100644
--- a/src/Plugin/CKEditorPlugin/MathJaxPlugin.php
+++ b/src/Plugin/CKEditorPlugin/MathJaxPlugin.php
@@ -26,13 +26,6 @@ class MathJaxPlugin extends CKEditorPluginBase implements ContainerFactoryPlugin
    */
   protected $libFileFinder;
 
-  /**
-   * File system.
-   *
-   * @var \Drupal\Core\File\FileSystem
-   */
-  protected $fileSystem;
-
   /**
    * Constructs a BlockComponentRenderArray object.
    *
@@ -44,20 +37,17 @@ class MathJaxPlugin extends CKEditorPluginBase implements ContainerFactoryPlugin
    *   The plugin implementation definition.
    * @param \Drupal\Core\Asset\LibrariesDirectoryFileFinder $libFileFinder
    *   The library file finder.
-   * @param \Drupal\Core\File\FileSystem $fileSystem
-   *   The file system.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, LibrariesDirectoryFileFinder $libFileFinder, FileSystem $fileSystem) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, LibrariesDirectoryFileFinder $libFileFinder) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->libFileFinder = $libFileFinder;
-    $this->fileSystem = $fileSystem;
   }
 
   /**
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
-    return new static($configuration, $plugin_id, $plugin_definition, $container->get('library.libraries_directory_file_finder'), $container->get('file_system'));
+    return new static($configuration, $plugin_id, $plugin_definition, $container->get('library.libraries_directory_file_finder'));
   }
 
   /**
@@ -95,7 +85,7 @@ class MathJaxPlugin extends CKEditorPluginBase implements ContainerFactoryPlugin
     return [
       'Mathjax' => [
         'label' => $this->t('Math'),
-        'image' => $this->fileSystem->realpath($this->libFileFinder->find('ckeditor-mathjax')) . '/icons/mathjax.png',
+        'image' => $this->libFileFinder->find('ckeditor-mathjax') . '/icons/mathjax.png',
       ],
     ];
   }
@@ -104,7 +94,7 @@ class MathJaxPlugin extends CKEditorPluginBase implements ContainerFactoryPlugin
    * {@inheritdoc}
    */
   public function getFile() {
-    return $this->fileSystem->realpath($this->libFileFinder->find('ckeditor-mathjax')) . '/plugin.js';
+    return $this->libFileFinder->find('ckeditor-mathjax') . '/plugin.js';
   }
 
 }