= f.inputs t_title(:list, SalaryItem) do
  %table#salary_items
    %thead
      = render 'salary_items/list_header', :template => f.object
    %tbody.sortable
      = f.fields_for :salary_items do |salary_item|
        = render 'salary_items/form', :salary_item => salary_item, :template => f.object

= f.inputs t_title(:list, SalaryItem) do
  %table#salary_items.nested-form-container
    %thead
      = render 'salary_items/list_header', :template => f.object
    %tbody.sortable
      = f.fields_for :salary_items do |salary_item|
        = render 'salary_items/form', :salary_item => salary_item, :template => f.object

Add .nested-form-container class in salary_item list form.
Add .nested-form-container class in salary_item list form.
