Issue #3314446: Do not initialise Inserter when there are no child nodes

js/insert.js

@@ -28,7 +28,10 @@
 
     // Initialize Inserter managing content insertion
     context.querySelectorAll('.insert').forEach(element => {
-      if (registry.find(inserter => inserter.container === element)) {
+      if (
+        !element.hasChildNodes()
+        || registry.find(inserter => inserter.container === element)
+      ) {
         return;
       }