diff --git a/extensions/mentions/js/src/forum/addComposerAutocomplete.js b/extensions/mentions/js/src/forum/addComposerAutocomplete.js
index c93ef2d44..7c7dac605 100644
--- a/extensions/mentions/js/src/forum/addComposerAutocomplete.js
+++ b/extensions/mentions/js/src/forum/addComposerAutocomplete.js
@@ -66,7 +66,7 @@ export default function addComposerAutocomplete() {
     const returnedUserIds = new Set(returnedUsers.map((u) => u.id()));
 
     const applySuggestion = (replacement) => {
-      app.composer.editor.replaceBeforeCursor(absMentionStart - 1, replacement + ' ');
+      this.attrs.composer.editor.replaceBeforeCursor(absMentionStart - 1, replacement + ' ');
 
       dropdown.hide();
     };