fix

admin/main/submenu/null_table/index.php

@@ -11,7 +11,7 @@ require_once($_SERVER['DOCUMENT_ROOT'].'/bitrix/modules/main/include/prolog_admi
  */
 $ormTable = resolve(NullTable::class);
 
-$tableAdminPage = new TableAdminPage($ormTable, $_REQUEST, '/bitrix/admin/bx_null.main.null_table.null_table_row.php');
+$tableAdminPage = new TableAdminPage($ormTable, $_REQUEST, '/bitrix/admin/bx_null.main.null_table.row.php');
 $tableAdminPage
     ->checkPermission()
     ->start()

admin/main/submenu/null_table/menu.php

@@ -9,4 +9,5 @@ Loc::loadMessages(__FILE__);
 return (new GlobalMenuItem())
     ->setSort(1300)
     ->setTitle('Null Table')
+    ->setIcon('iblock_menu_icon_iblocks')
     ->setUrl();

admin/main/submenu/null_table/submenu/row/menu.php

@@ -8,5 +8,6 @@ Loc::loadMessages(__FILE__);
 return (new GlobalMenuItem())
     ->setSort(1400)
     ->setTitle('Null Table Row')
+    ->setIcon('default_menu_icon')
     ->setVisible(false)
     ->setUrl();