diff --git a/app/models/report.rb b/app/models/report.rb
index 1686fa725..84556d095 100644
--- a/app/models/report.rb
+++ b/app/models/report.rb
@@ -116,7 +116,7 @@ class Report < ApplicationRecord
           'type_of' => element[:type_of] || element[:type_of_lambda].call(object),
           'id' => { element[:id_key] => object.id },
           'sort_order' => element[:sort_order],
-          'children' => gen_element_content(object, element[:children])
+          'children' => gen_element_content(object, element[:children] || [])
         }
         hash_object['id'][element[:parent_id_key]] = parent.id if element[:parent_id_key]
         hash_object
diff --git a/config/initializers/extends.rb b/config/initializers/extends.rb
index 15519fc2a..025d54ef8 100644
--- a/config/initializers/extends.rb
+++ b/config/initializers/extends.rb
@@ -45,7 +45,6 @@ class Extends
     {
       type_of: 'project_header',
       id_key: 'project_id',
-      children: []
     },
     {
       type_of: 'experiment',
@@ -60,7 +59,6 @@ class Extends
             {
               type_of: 'my_module_protocol',
               id_key: 'my_module_id',
-              children: []
             },
             {
               type_of: 'step',
@@ -71,25 +69,21 @@ class Extends
                   type_of: 'step_asset',
                   relation: %w(assets),
                   id_key: 'asset_id',
-                  children: []
                 },
                 {
                   type_of: 'step_table',
                   relation: %w(tables),
                   id_key: 'table_id',
-                  children: []
                 },
                 {
                   type_of: 'step_checklist',
                   relation: %w(checklists),
                   id_key: 'checklist_id',
-                  children: []
                 },
                 {
                   type_of: 'step_comments',
                   id_key: 'step_id',
                   sort_order: 'asc',
-                  children: []
                 }
               ]
             },
@@ -104,23 +98,20 @@ class Extends
               children: [{
                 type_of: 'result_comments',
                 id_key: 'result_id',
-                sort_order: 'asc',
-                children: []
+                sort_order: 'asc'
               }]
             },
             {
               type_of: 'my_module_activity',
               id_key: 'my_module_id',
-              sort_order: 'asc',
-              children: []
+              sort_order: 'asc'
             },
             {
               type_of: 'my_module_repository',
               relation: %w(experiment project assigned_repositories_and_snapshots),
               id_key: 'repository_id',
               parent_id_key: 'my_module_id',
-              sort_order: 'asc',
-              children: []
+              sort_order: 'asc'
             }
           ]
         }