diff --git a/app/assets/stylesheets/alchemy/elements.scss b/app/assets/stylesheets/alchemy/elements.scss
index bd2b94b81b..c4ba3bf32a 100644
--- a/app/assets/stylesheets/alchemy/elements.scss
+++ b/app/assets/stylesheets/alchemy/elements.scss
@@ -15,7 +15,7 @@
   }
 
   // Fix for Tinymce fullscreen window positioning issues (GH#1511)
-  .mce-fullscreen & {
+  .tox-fullscreen & {
     width: calc(100vw - #{$collapsed-main-menu-width - $default-border-width});
   }