diff --git a/Configuration/ElFinderConfigurationReader.php b/Configuration/ElFinderConfigurationReader.php
index 9ce978d..4150b97 100644
--- a/Configuration/ElFinderConfigurationReader.php
+++ b/Configuration/ElFinderConfigurationReader.php
@@ -104,7 +104,7 @@ public function getConfiguration($instance)
                 'imgLib'            => $parameter['img_lib'],
                 'tmbPath'           => $parameter['tmb_path'],
                 'tmbPathMode'       => $parameter['tmb_path_mode'],
-                'tmbUrl'            => $parameter['tmb_url'],
+                'tmbURL'            => $parameter['tmb_url'],
                 'tmbSize'           => $parameter['tmb_size'],
                 'tmbCrop'           => $parameter['tmb_crop'],
                 'tmbBgColor'        => $parameter['tmb_bg_color'],
diff --git a/Tests/Configuration/ElFinderConfigurationReaderTest.php b/Tests/Configuration/ElFinderConfigurationReaderTest.php
index 4b5280c..e445776 100644
--- a/Tests/Configuration/ElFinderConfigurationReaderTest.php
+++ b/Tests/Configuration/ElFinderConfigurationReaderTest.php
@@ -303,4 +303,10 @@ public function testPathAndUrlAndHomeFolder()
         $this->assertEquals('/bob', $configuration['roots'][0]['path']);
         $this->assertEquals('http://test.com/unit-test/home-url-without-path/bob', $configuration['roots'][0]['URL']);
     }
+
+    public function testAccessTmbURLOpion()
+    {
+        $configuration = $this->reader->getConfiguration('default');
+        $this->assertArrayHasKey('tmbURL', $configuration['roots'][0]);
+    }
 }