diff --git a/docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/04_Preview.md b/docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/04_Preview.md
index f949d9717..513f4e711 100644
--- a/docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/04_Preview.md
+++ b/docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/04_Preview.md
@@ -72,9 +72,9 @@ Load the file in the CMS via setting adding 'mysite/javascript/MyLeftAndMain.Pre
 to the `LeftAndMain.extra_requirements_javascript` [configuration value](/topics/configuration)
 
 	:::yml
-	LeftAndMain
+	LeftAndMain:
 	  extra_requirements_javascript:
-	    - mysite/javascript/MyLeftAndMain.Preview.js:
+	    - mysite/javascript/MyLeftAndMain.Preview.js
 
 In order to find out which configuration values are available, the source code
 is your best reference at the moment - have a look in `framework/admin/javascript/LeftAndMain.Preview.js`.