app/views/setup/activities/_constant.html.erb
<tr>
<td width="50%"><%= f.input :name, input_html: {value: f.object.name || @activity.name} %></td>
<td><%= f.input :state_id , collection: states%></td>
<td><%= f.input :formula %></td>
<%= f.hidden_field :kind, value: 'formula' %>
</tr>