fix #2791

Closes #2791

Merge request studip/studip!2075

resources/vue/components/courseware/CoursewareTree.vue

@@ -238,6 +238,11 @@ export default {
     },
     mounted() {
         this.updateNestedChildren();
+    },
+    watch: {
+        structuralElements() {
+            this.updateNestedChildren();
+        }
     }
 };
 </script>